大家好，欢迎来到IT知识分享网。
java命令行
| 序号 | 接口 |
|---|---|
| java | Java 应用的启动程序 |
| javac | JDK 内置的编译工具 |
| javap | 反编译 class 文件的工具 |
| javadoc | 根据 Java 代码和标准注释,自动生成相关的 API 说明文档 |
| javah | JNI 开发时, 根据 java 代码生成需要的 .h文件 |
| extcheck | 检查某个 jar 文件和运行时扩展 jar 有没有版本冲突，很少使用 |
| jdb | Java Debugger ; 可以调试本地和远端程序，属于 JPDA 中的一个 demo 实现，供其他调试器参考。开发时很少使用 |
| jdeps | 探测 class 或 jar 包需要的依赖 |
| jar | 打包工具，可以将文件和目录打包成为 .jar 文件；.jar 文件本质上就是 zip 文件, 只是后缀不同。使用时按顺序对应好选项和参数即可。 |
| keytool | 安全证书和密钥的管理工具; （支持生成、导入、导出等操作） |
| jarsigner | JAR 文件签名和验证工具 |
| policytool | 实际上这是一款图形界面工具, 管理本机的 Java 安全策略 |
| jps/jinfo | 查看 java 进程 |
| jstat | 查看 JVM 内部 gc 相关信息 |
| jmap | 查看 heap 或类占用空间统计 |
| jstack | 查看线程信息 |
| jcmd | 执行 JVM 相关分析命令（整合命令） |
| jrunscript/jjs | 执行 js 命令 |
一. jps
1. jps：查看当前 java 进程
18724 NodeManager 18280 SecondaryNameNode 20651 HMaster 17357 QuorumPeerMain 20848 HRegionServer 17841 NameNode Kafka 18038 DataNode 18550 ResourceManager Jps 21466 Worker 21372 Master 22269 jar 2. jps -q: 只显示 java 进程号
18724 18280 20651 17357 20848 17841 18038 18550 21466 21372 22269 3. jps –l：输出主类或者 jar 的完全路径名
sun.tools.jps.Jps 18724 org.apache.hadoop.yarn.server.nodemanager.NodeManager 18280 org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode 20651 org.apache.hadoop.hbase.master.HMaster 17357 org.apache.zookeeper.server.quorum.QuorumPeerMain 20848 org.apache.hadoop.hbase.regionserver.HRegionServer 17841 org.apache.hadoop.hdfs.server.namenode.NameNode kafka.Kafka 18038 org.apache.hadoop.hdfs.server.datanode.DataNode 18550 org.apache.hadoop.yarn.server.resourcemanager.ResourceManager 21466 org.apache.spark.deploy.worker.Worker 21372 org.apache.spark.deploy.master.Master 22269 api-test.jar 4. jps -m: 输出 main 方法的启动参数
18724 NodeManager 18280 SecondaryNameNode 20651 HMaster start 17357 QuorumPeerMain /opt/software/zookeeper-3.4.14/bin/../conf/zoo.cfg 20848 HRegionServer start 17841 NameNode Kafka ../config/server.properties Jps -m 18038 DataNode 18550 ResourceManager 21466 Worker --webui-port 8081 spark://172.29.38.64:7077 21372 Master --host 172.29.38.64 --port 7077 --webui-port 8081 22269 jar 5. jps -v: 输出jvm参数
18724 NodeManager -Dproc_nodemanager -Djava.net.preferIPv4Stack=true -Dyarn.log.dir=/opt/software/hadoop-3.2.2/logs -Dyarn.log.file=hadoop-root-nodemanager-ashen-friede.log -Dyarn.home.dir=/opt/software/hadoop-3.2.2 -Dyarn.root.logger=INFO,console -Djava.library.path=/opt/software/hadoop-3.2.2/lib/native -Dhadoop.log.dir=/opt/software/hadoop-3.2.2/logs -Dhadoop.log.file=hadoop-root-nodemanager-ashen-friede.log -Dhadoop.home.dir=/opt/software/hadoop-3.2.2 -Dhadoop.id.str=root -Dhadoop.root.logger=INFO,RFA -Dhadoop.policy.file=hadoop-policy.xml -Dhadoop.security.logger=INFO,NullAppender 18280 SecondaryNameNode -Dproc_secondarynamenode -Djava.net.preferIPv4Stack=true -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dyarn.log.dir=/opt/software/hadoop-3.2.2/logs -Dyarn.log.file=hadoop-root-secondarynamenode-ashen-friede.log -Dyarn.home.dir=/opt/software/hadoop-3.2.2 -Dyarn.root.logger=INFO,console -Djava.library.path=/opt/software/hadoop-3.2.2/lib/native -Dhadoop.log.dir=/opt/software/hadoop-3.2.2/logs -Dhadoop.log.file=hadoop-root-secondarynamenode-ashen-friede.log -Dhadoop.home.dir=/opt/software/hadoop-3.2.2 -Dhadoop.id.str=root -Dhadoop.root.logger=INFO,RFA -Dhadoop.policy.file=hadoop-policy.xml 20651 HMaster -Dproc_master -XX:OnOutOfMemoryError=kill -9 %p -XX:+UseConcMarkSweepGC -XX:PermSize=128m -XX:MaxPermSize=128m -XX:ReservedCodeCacheSize=256m -Dhbase.log.dir=/opt/software/hbase-1.4.13/logs -Dhbase.log.file=hbase-root-master-ashen-friede.log -Dhbase.home.dir=/opt/software/hbase-1.4.13 -Dhbase.id.str=root -Dhbase.root.logger=INFO,RFA -Djava.library.path=/opt/software/hadoop-3.2.2/lib:/opt/software/hadoop-3.2.2/lib/native -Dhbase.security.logger=INFO,RFAS 17357 QuorumPeerMain -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false 20848 HRegionServer -Dproc_regionserver -XX:OnOutOfMemoryError=kill -9 %p -XX:+UseConcMarkSweepGC -XX:PermSize=128m -XX:MaxPermSize=128m -XX:ReservedCodeCacheSize=256m -Dhbase.log.dir=/opt/software/hbase-1.4.13/bin/../logs -Dhbase.log.file=hbase-root-regionserver-ashen-friede.log -Dhbase.home.dir=/opt/software/hbase-1.4.13/bin/.. -Dhbase.id.str=root -Dhbase.root.logger=INFO,RFA -Dhbase.security.logger=INFO,RFAS 17841 NameNode -Dproc_namenode -Djava.net.preferIPv4Stack=true -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dyarn.log.dir=/opt/software/hadoop-3.2.2/logs -Dyarn.log.file=hadoop-root-namenode-ashen-friede.log -Dyarn.home.dir=/opt/software/hadoop-3.2.2 -Dyarn.root.logger=INFO,console -Djava.library.path=/opt/software/hadoop-3.2.2/lib/native -Dhadoop.log.dir=/opt/software/hadoop-3.2.2/logs -Dhadoop.log.file=hadoop-root-namenode-ashen-friede.log -Dhadoop.home.dir=/opt/software/hadoop-3.2.2 -Dhadoop.id.str=root -Dhadoop.root.logger=INFO,RFA -Dhadoop.policy.file=hadoop-policy.xml Kafka -Xmx1G -Xms1G -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -XX:MaxInlineLevel=15 -Djava.awt.headless=true -Xloggc:/opt/software/kafka_2.12-3.0.0/bin/../logs/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=100M -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/opt/software/kafka_2.12-3.0.0/bin/../logs -Dlog4j.configuration=file:./../config/log4j.properties Jps -Denv.class.path=.:/usr/java/jdk1.8.0_151/lib/dt.jar:/usr/java/jdk1.8.0_151/lib/tools.jar:/opt/software/hadoop-3.2.2/lib/*.jar:/opt/software/hadoop-3.2.2/share/hadoop/client/*.jar:/opt/software/hadoop-3.2.2/share/hadoop/common/*.jar:/opt/software/hadoop-3.2.2/share/hadoop/hdfs/*.jar:/opt/software/hadoop-3.2.2/share/hadoop/mapreduce/*.jar:/opt/software/hadoop-3.2.2/share/hadoop/yarn/*.jar:/opt/software/hbase-1.4.13/lib/ -Dapplication.home=/usr/java/jdk1.8.0_151 -Xms8m 18038 DataNode -Dproc_datanode -Djava.net.preferIPv4Stack=true -Dhadoop.security.logger=ERROR,RFAS -Dyarn.log.dir=/opt/software/hadoop-3.2.2/logs -Dyarn.log.file=hadoop-root-datanode-ashen-friede.log -Dyarn.home.dir=/opt/software/hadoop-3.2.2 -Dyarn.root.logger=INFO,console -Djava.library.path=/opt/software/hadoop-3.2.2/lib/native -Dhadoop.log.dir=/opt/software/hadoop-3.2.2/logs -Dhadoop.log.file=hadoop-root-datanode-ashen-friede.log -Dhadoop.home.dir=/opt/software/hadoop-3.2.2 -Dhadoop.id.str=root -Dhadoop.root.logger=INFO,RFA -Dhadoop.policy.file=hadoop-policy.xml 18550 ResourceManager -Dproc_resourcemanager -Djava.library.path=/opt/software/hadoop-3.2.2/lib:/opt/software/hadoop-3.2.2/lib/native -Dservice.libdir=/opt/software/hadoop-3.2.2/share/hadoop/yarn,/opt/software/hadoop-3.2.2/share/hadoop/yarn/lib,/opt/software/hadoop-3.2.2/share/hadoop/hdfs,/opt/software/hadoop-3.2.2/share/hadoop/hdfs/lib,/opt/software/hadoop-3.2.2/share/hadoop/common,/opt/software/hadoop-3.2.2/share/hadoop/common/lib -Dyarn.log.dir=/opt/software/hadoop-3.2.2/logs -Dyarn.log.file=hadoop-root-resourcemanager-ashen-friede.log -Dyarn.home.dir=/opt/software/hadoop-3.2.2 -Dyarn.root.logger=INFO,console -Dhadoop.log.dir=/opt/software/hadoop-3.2.2/logs -Dhadoop.log.file=hadoop-root-resourcemanager-ashen-friede.log -Dhadoop.home.dir=/opt/software/hadoop-3.2.2 -Dhadoop.id.str=root -Dhadoop.root.logger=INFO,RFA -Dhadoop.policy.file=hadoop-policy.xml -Dhadoop.security.logger=INFO,NullAppender 21466 Worker -Xmx1g 21372 Master -Xmx1g 22269 jar 二.jinfo
1. jinfo -[pid]
输出全部的参数和系统属性
Attaching to process ID 22269, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 Java System Properties: java.runtime.name = Java(TM) SE Runtime Environment java.vm.version = 25.151-b12 sun.boot.library.path = /usr/java/jdk1.8.0_151/jre/lib/amd64 java.protocol.handler.pkgs = org.springframework.boot.loader java.vendor.url = http://java.oracle.com/ java.vm.vendor = Oracle Corporation path.separator = : file.encoding.pkg = sun.io java.vm.name = Java HotSpot(TM) 64-Bit Server VM sun.os.patch.level = unknown sun.java.launcher = SUN_STANDARD user.country = US user.dir = /server/api-test java.vm.specification.name = Java Virtual Machine Specification PID = 22269 java.runtime.version = 1.8.0_151-b12 java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment os.arch = amd64 java.endorsed.dirs = /usr/java/jdk1.8.0_151/jre/lib/endorsed line.separator = java.io.tmpdir = /tmp java.vm.specification.vendor = Oracle Corporation os.name = Linux sun.jnu.encoding = UTF-8 java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib spring.beaninfo.ignore = true java.specification.name = Java Platform API Specification java.class.version = 52.0 sun.management.compiler = HotSpot 64-Bit Tiered Compilers os.version = 4.18.0-348.2.1.el8_5.x86_64 user.home = /root user.timezone = Asia/Shanghai catalina.useNaming = false java.awt.printerjob = sun.print.PSPrinterJob file.encoding = UTF-8 java.specification.version = 1.8 catalina.home = /tmp/tomcat..8086 user.name = root java.class.path = api-test.jar java.vm.specification.version = 1.8 sun.arch.data.model = 64 sun.java.command = api-test.jar java.home = /usr/java/jdk1.8.0_151/jre user.language = en java.specification.vendor = Oracle Corporation awt.toolkit = sun.awt.X11.XToolkit java.vm.info = mixed mode java.version = 1.8.0_151 java.ext.dirs = /usr/java/jdk1.8.0_151/jre/lib/ext:/usr/java/packages/lib/ext sun.boot.class.path = /usr/java/jdk1.8.0_151/jre/lib/resources.jar:/usr/java/jdk1.8.0_151/jre/lib/rt.jar:/usr/java/jdk1.8.0_151/jre/lib/sunrsasign.jar:/usr/java/jdk1.8.0_151/jre/lib/jsse.jar:/usr/java/jdk1.8.0_151/jre/lib/jce.jar:/usr/java/jdk1.8.0_151/jre/lib/charsets.jar:/usr/java/jdk1.8.0_151/jre/lib/jfr.jar:/usr/java/jdk1.8.0_151/jre/classes java.awt.headless = true java.vendor = Oracle Corporation catalina.base = /tmp/tomcat..8086 file.separator = / java.vendor.url.bug = http://bugreport.sun.com/bugreport/ sun.io.unicode.encoding = UnicodeLittle sun.cpu.endian = little sun.cpu.isalist = VM Flags: Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize= -XX:MaxHeapSize= -XX:MaxNewSize= -XX:MinHeapDeltaBytes= -XX:NewSize= -XX:OldSize= -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:+UseParallelGC Command line: 2. jinfo -flag [name] pid
输出对应名称的参数:
jinfo -flag MaxHeapSize 22269 输出:
[root@ashen-friede ~]# jinfo -flag MaxHeapSize 22269 -XX:MaxHeapSize= 3. jinfo -flag [+|-][name] pid
在不重启虚拟机的情况下，可以动态的修改 jvm 的参数。尤其在线上的环境特别有用。
减少配置
jinfo -flag -PrintGC 22269 [root@ashen-friede ~]# jinfo -flag -PrintGC 22269 [root@ashen-friede ~]# jinfo -flag PrintGC 22269 -XX:-PrintGC 增加配置
jinfo -flag +PrintGC 22269 [root@ashen-friede ~]# jinfo -flag +PrintGC 22269 [root@ashen-friede ~]# jinfo -flag PrintGC 22269 -XX:+PrintGC 4. jinfo -flag [name]=[value] pid
在不重启虚拟机的情况下，可以动态的修改 jvm 的参数值。尤其在线上的环境特别有用。
jinfo -flag HeapDumpPath=/mnt/test.hprof 22269 输出:
[root@ashen-friede ~]# jinfo -flag HeapDumpPath 22269 -XX:HeapDumpPath= [root@ashen-friede ~]# jinfo -flag HeapDumpPath=/mnt/test.hprof 22269 [root@ashen-friede ~]# jinfo -flag HeapDumpPath 22269 -XX:HeapDumpPath=/mnt/test.hprof 并不是所有的参数都支持动态修改
5. jinfo -flags pid
输出全部的参数
jinfo -flags 22269 输出:
[root@ashen-friede ~]# jinfo -flags 22269 Attaching to process ID 22269, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 Non-default VM flags: -XX:CICompilerCount=3 -XX:HeapDumpPath=null -XX:InitialHeapSize= -XX:MaxHeapSize= -XX:MaxNewSize= -XX:MinHeapDeltaBytes= -XX:NewSize= -XX:OldSize= -XX:-PrintGC -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:+UseParallelGC Command line: 6. jinfo -sysprops pid
jinfo -sysprops 22269 输出:
[root@ashen-friede ~]# jinfo -sysprops 22269 Attaching to process ID 22269, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 java.runtime.name = Java(TM) SE Runtime Environment java.vm.version = 25.151-b12 sun.boot.library.path = /usr/java/jdk1.8.0_151/jre/lib/amd64 java.protocol.handler.pkgs = org.springframework.boot.loader java.vendor.url = http://java.oracle.com/ java.vm.vendor = Oracle Corporation path.separator = : file.encoding.pkg = sun.io java.vm.name = Java HotSpot(TM) 64-Bit Server VM sun.os.patch.level = unknown sun.java.launcher = SUN_STANDARD user.country = US user.dir = /server/api-test java.vm.specification.name = Java Virtual Machine Specification PID = 22269 java.runtime.version = 1.8.0_151-b12 java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment os.arch = amd64 java.endorsed.dirs = /usr/java/jdk1.8.0_151/jre/lib/endorsed line.separator = java.io.tmpdir = /tmp java.vm.specification.vendor = Oracle Corporation os.name = Linux sun.jnu.encoding = UTF-8 java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib spring.beaninfo.ignore = true java.specification.name = Java Platform API Specification java.class.version = 52.0 sun.management.compiler = HotSpot 64-Bit Tiered Compilers os.version = 4.18.0-348.2.1.el8_5.x86_64 user.home = /root user.timezone = Asia/Shanghai catalina.useNaming = false java.awt.printerjob = sun.print.PSPrinterJob file.encoding = UTF-8 java.specification.version = 1.8 catalina.home = /tmp/tomcat..8086 user.name = root java.class.path = api-test.jar java.vm.specification.version = 1.8 sun.arch.data.model = 64 sun.java.command = api-test.jar java.home = /usr/java/jdk1.8.0_151/jre user.language = en java.specification.vendor = Oracle Corporation awt.toolkit = sun.awt.X11.XToolkit java.vm.info = mixed mode java.version = 1.8.0_151 java.ext.dirs = /usr/java/jdk1.8.0_151/jre/lib/ext:/usr/java/packages/lib/ext sun.boot.class.path = /usr/java/jdk1.8.0_151/jre/lib/resources.jar:/usr/java/jdk1.8.0_151/jre/lib/rt.jar:/usr/java/jdk1.8.0_151/jre/lib/sunrsasign.jar:/usr/java/jdk1.8.0_151/jre/lib/jsse.jar:/usr/java/jdk1.8.0_151/jre/lib/jce.jar:/usr/java/jdk1.8.0_151/jre/lib/charsets.jar:/usr/java/jdk1.8.0_151/jre/lib/jfr.jar:/usr/java/jdk1.8.0_151/jre/classes java.awt.headless = true java.vendor = Oracle Corporation catalina.base = /tmp/tomcat..8086 file.separator = / java.vendor.url.bug = http://bugreport.sun.com/bugreport/ sun.io.unicode.encoding = UnicodeLittle sun.cpu.endian = little sun.cpu.isalist = 三. jstat
对Java应用程序的资源和性能进行实时的命令行的监控，包括了对Heap size和垃圾回收状况的监控.
1.jstat -class [pid]
显示加载class的数量，及所占空间等信息。
jstat -class 22269 [root@ashen-friede ~]# jstat -class 22269 Loaded Bytes Unloaded Bytes Time 7604 13807.4 1 0.9 4.30 | 列 | 说明 |
|---|---|
| Loaded | 装载的类的数量 |
| Bytes | 装载类所占用的字节数 |
| Unloaded | 卸载类的数量 |
| Bytes | 卸载类的字节数 |
| Time | 装载和卸载类所花费的时间 |
2.jstat -compiler [pid]
JIT 即时编译器相关的统计信息
jstat -compiler 22269 输出:
[root@ashen-friede ~]# jstat -compiler 22269 Compiled Failed Invalid Time FailedType FailedMethod 6540 0 0 21.65 0 | 列 | 说明 |
|---|---|
| Compiled | 编译任务执行数量 |
| Failed | 编译任务执行失败数量 |
| Invalid | 编译任务执行失效数量 |
| Time | 编译任务消耗时间 |
| FailedType | 最后一个编译失败任务的类型 |
| FailedMethod | 最后一个编译失败任务所在的类及方法 |
3.jstat -gc [pid] [time默认毫秒]
显示gc的信息，查看gc的次数，及时间
3.1 打印 gc 信息
jstat -gc 22269 输出:
[root@ashen-friede ~]# jstat -gc 22269 S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 | 列 | 说明 |
|---|---|
| S0C | 年轻代中第一个survivor（幸存区）的容量(字节) |
| S1C | 年轻代中第二个survivor（幸存区）的容量(字节) |
| S0U | 年轻代中第一个survivor（幸存区）目前已使用空间(字节) |
| S1U | 年轻代中第二个survivor（幸存区）目前已使用空间(字节) |
| EC | 年轻代中Eden（伊甸园）的容量(字节) |
| EU | 年轻代中Eden（伊甸园）目前已使用空间(字节) |
| OC | Old代的容量(字节) |
| OU | Old代目前已使用空间(字节) |
| PC | Perm(持久代)的容量(字节) |
| PU | Perm(持久代)目前已使用空间(字节) |
| YGC | 从应用程序启动到采样时年轻代中gc次数 |
| YGCT | 从应用程序启动到采样时年轻代中gc所用时间(s) |
| FGC | 从应用程序启动到采样时old代(全gc)gc次数 |
| FGCT | 从应用程序启动到采样时old代(全gc)gc所用时间(s) |
| GCT | 从应用程序启动到采样时gc用的总时间(s) |
3.2 每隔 5s 打印 gc 信息
jstat -gc 22269 5000 输出:
[root@ashen-friede ~]# jstat -gc 22269 5000 S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 5120.0 8192.0 5008.2 0.0 .0 .5 97280.0 15881.1 43056.0 41137.6 5424.0 5067.7 12 0.129 2 0.180 0.309 3.3 每隔 10 行打印表头, 每隔 1s 打印一次gc信息 并打印 jar 包启动时间
jstat -gc -h 10 -t 1s 输出:
[root@ashen-friede mnt]# jstat -gc -h 10 -t 1s Timestamp S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 8089.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8090.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8091.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8092.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8093.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8094.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8095.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8096.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8097.5 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8098.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 Timestamp S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 8099.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8100.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8101.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8102.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8103.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 8104.6 9216.0 9728.0 0.0 0.0 .0 27366.1 .0 15647.1 38912.0 36872.3 5120.0 4726.8 9 0.115 3 0.304 0.420 | 参数 | 接口 |
|---|---|
| -h [count] | 每隔十行打印一次表头 |
| -t | 打印时间, 该时间为系统启动的秒数 |
4.jstat -gccapacity [pid]
打印各个内存池分代空间的容量
jstat -gccapacity [root@ashen-friede api-test]# jstat -gccapacity NGCMN NGCMX NGC S0C S1C EC OGCMN OGCMX OGC OC MCMN MCMX MC CCSMN CCSMX CCSC YGC FGC 41472.0 .0 .0 6144.0 9728.0 .0 83456.0 .0 87040.0 87040.0 0.0 .0 35456.0 0.0 .0 4736.0 8 2 | 列 | 说明 |
|---|---|
| NGCMN | 年轻代(young)中初始化(最小)的大小(字节) |
| NGCMX | 年轻代(young)的最大容量(字节) |
| NGC | 年轻代(young)中当前的容量(字节) |
| S0C | 年轻代中第一个survivor（幸存区）的容量(字节) |
| S1C | 年轻代中第二个survivor（幸存区）的容量(字节) |
| EC | 年轻代中Eden（伊甸园）的容量(字节) |
| OGCMN | old代中初始化(最小)的大小(字节) |
| OGCMX | old代的最大容量(字节) |
| OGC | old代当前新生成的容量(字节) |
| OC | Old代的容量(字节) |
| PGCMN | perm代中初始化(最小)的大小(字节) |
| PGCMX | perm代的最大容量(字节) |
| PGC | perm代当前新生成的容量(字节) |
| PC | Perm(持久代)的容量(字节) |
| YGC | 从应用程序启动到采样时年轻代中gc次数 |
| FGC | 从应用程序启动到采样时old代(全gc)gc次数 |
其他用法与 -gc 类似
5.jstat -gcutil [pid]
GC 相关区域的使用率（utilization）统计
jstat -gcutil 输出:
[root@ashen-friede api-test]# jstat -gcutil S0 S1 E O M CCS YGC YGCT FGC FGCT GCT 0.00 0.00 65.87 18.50 95.85 91.98 8 0.101 2 0.194 0.294 | 列 | 说明 |
|---|---|
| S0 | 年轻代中第一个survivor（幸存区）已使用的占当前容量百分比 |
| S1 | 年轻代中第二个survivor（幸存区）已使用的占当前容量百分比 |
| E | 年轻代中Eden（伊甸园）已使用的占当前容量百分比 |
| O | old代已使用的占当前容量百分比 |
| P | perm代已使用的占当前容量百分比 |
| YGC | 从应用程序启动到采样时年轻代中gc次数 |
| YGCT | 从应用程序启动到采样时年轻代中gc所用时间(s) |
| FGC | 从应用程序启动到采样时old代(全gc)gc次数 |
| FGCT | 从应用程序启动到采样时old代(全gc)gc所用时间(s) |
| GCT | 从应用程序启动到采样时gc用的总时间(s) |
其他用法与 -gc 类似
6.jstat -gccause [pid]
看上次 GC，本次 GC（如果正在 GC 中）的原因， 其他输出和 -gcutil 选项一致
jstat -gccause 输出:
[root@ashen-friede api-test]# jstat -gccause S0 S1 E O M CCS YGC YGCT FGC FGCT GCT LGCC GCC 0.00 0.00 65.87 18.50 95.85 91.98 8 0.101 2 0.194 0.294 Metadata GC Threshold No GC | 列 | 说明 |
|---|---|
| LGCC | 上次垃圾回收的原因 |
| GCC | 当前垃圾回收的原因 |
其他参数与 -gcutil 一致
7.jstat -gcnew [pid]
年轻代的统计信息。（New = Young = Eden + S0 + S1） -gcnewcapacity 年轻代空间大小统计
jstat -gcnew 输出:
[root@ashen-friede api-test]# jstat -gcnew S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT 6144.0 9728.0 0.0 0.0 3 15 9728.0 .0 .4 8 0.101 | 列 | 说明 |
|---|---|
| S0C | 年轻代中第一个survivor（幸存区）的容量(字节) |
| S1C | 年轻代中第二个survivor（幸存区）的容量(字节) |
| S0U | 年轻代中第一个survivor（幸存区）目前已使用空间(字节) |
| S1U | 年轻代中第二个survivor（幸存区）目前已使用空间(字节) |
| TT | 持有次数限制 |
| MTT | 最大持有次数限制 |
| EC | 年轻代中Eden（伊甸园）的容量(字节) |
| EU | 年轻代中Eden（伊甸园）目前已使用空间(字节) |
| YGC | 从应用程序启动到采样时年轻代中gc次数 |
| YGCT | 从应用程序启动到采样时年轻代中gc所用时间(s) |
8.jstat -gcold [pid]
老年代和元数据区的行为统计
jstat -gcold 输出:
[root@ashen-friede api-test]# jstat -gcold MC MU CCSC CCSU OC OU YGC FGC FGCT GCT 35456.0 33983.7 4736.0 4356.0 87040.0 16105.1 8 2 0.194 0.294 | 列 | 说明 |
|---|---|
| MC | 方法区大小 |
| MU | 方法区使用大小 |
| CCSC | 压缩类空间大小 |
| CCSU | 压缩类空间使用大小 |
| OC | Old代的容量(字节) |
| OU | Old代目前已使用空间(字节) |
| YGC | 从应用程序启动到采样时年轻代中gc次数 |
| FGC | 从应用程序启动到采样时old代(全gc)gc次数 |
| FGCT | 从应用程序启动到采样时old代(全gc)gc所用时间(s) |
| GCT | 从应用程序启动到采样时gc用的总时间(s) |
9.jstat -gcoldcapacity [pid]
old代空间大小统计
jstat -gcoldcapacity 输出:
[root@ashen-friede api-test]# jstat -gcoldcapacity OGCMN OGCMX OGC OC YGC FGC FGCT GCT 83456.0 .0 87040.0 87040.0 8 2 0.194 0.294 | 列 | 说明 |
|---|---|
| OGCMN | 老年代最小容量 |
| OGCMX | 老年代最大容量 |
| OGC | 当前老年代大小 |
| OC | 老年代大小 |
| YGC | 年轻代垃圾回收次数 |
| FGC | 老年代垃圾回收次数 |
| FGCT | 老年代垃圾回收消耗时间 |
| GCT | 垃圾回收消耗总时间 |
10.jstat -gcmetacapacity [pid]
meta 区大小统计
jstat -gcmetacapacity 输出:
[root@ashen-friede api-test]# jstat -gcmetacapacity MCMN MCMX MC CCSMN CCSMX CCSC YGC FGC FGCT GCT 0.0 .0 35456.0 0.0 .0 4736.0 8 2 0.194 0.294 | 列 | 说明 |
|---|---|
| MCMN | 最小元数据容量 |
| MCMX | 最大元数据容量 |
| MC | 当前元数据空间大小 |
| CCSMN | 最小压缩类空间大小 |
| CCSMX | 最大压缩类空间大小 |
| CCSC | 当前压缩类空间大小 |
| YGC | 年轻代垃圾回收次数 |
| FGC | 老年代垃圾回收次数 |
| FGCT | 老年代垃圾回收消耗时间 |
| GCT | 垃圾回收消耗总时间 |
11.jstat -printcompilation [pid]
打印 JVM 编译统计信息
jstat -printcompilation 输出:
[root@ashen-friede api-test]# jstat -printcompilation Compiled Size Type Method 3650 1020 1 sun/nio/ch/SelectorImpl lockAndDoSelect | 列 | 说明 |
|---|---|
| Compiled | 最近编译方法的数量 |
| Size | 最近编译方法的字节码数量 |
| Type | 最近编译方法的编译类型。 |
| Method | 方法名标识。 |
四. jmap
jmap命令是一个可以输出所有内存中对象的工具，甚至可以将 JVM 中的heap，以二进制输出成文本。打印出某个java进程（使用pid）内存内的，所有对象的情况（产生那些对象，及其数量）。
1.jmap -heap [pid]
打印堆内存（/内存池）的配置和使用信息。
jmap -heap 输出:
[root@ashen-friede api-test]# jmap -heap Attaching to process ID , please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 using thread-local object allocation. Parallel GC with 4 thread(s) Heap Configuration: MinHeapFreeRatio = 0 MaxHeapFreeRatio = 100 MaxHeapSize = (1944.0MB) NewSize = (40.5MB) MaxNewSize = (648.0MB) OldSize = (81.5MB) NewRatio = 2 SurvivorRatio = 8 MetaspaceSize = (20.MB) CompressedClassSpaceSize = (1024.0MB) MaxMetaspaceSize = 415 MB G1HeapRegionSize = 0 (0.0MB) Heap Usage: PS Young Generation Eden Space: capacity = (184.5MB) used = (121.844MB) free = (62.156MB) 65.869% used From Space: capacity = (6.0MB) used = 0 (0.0MB) free = (6.0MB) 0.0% used To Space: capacity = (9.5MB) used = 0 (0.0MB) free = (9.5MB) 0.0% used PS Old Generation capacity = (85.0MB) used = (15.8906MB) free = (69.11MB) 18.0476% used 16170 interned Strings occupying bytes. 2.jmap -histo [pid]
查看堆内存(histogram)中的对象数量，大小
jmap -histo | 列 | 说明 |
|---|---|
| num | 序号 |
| instances | 实例个数 |
| bytes | 字节数 |
| class name | 类名 |
3.jmap -dump:format=b,file=[filename].hprof [pid]
Dump 堆内存到 hprof 文件
jmap -dump:format=b,file=/mnt/test.hprof 然后可以使用 jvisualvm 类似的工具查看
[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-xkqpSEHU-54)(3.png)]
五. jstack
jstack是java虚拟机自带的一种堆栈跟踪工具。jstack用于打印出给定的java进程ID或core file或远程调试服务的Java堆栈信息。
1.jstack -l [pid]
长列表模式，将线程相关的 locks 信息一起输出，比如持有的锁，等待的锁，死锁等信息
jstack -l [root@ashen-friede mnt]# jstack -l 2022-03-11 13:22:31 Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.151-b12 mixed mode): "Attach Listener" #31 daemon prio=9 os_prio=0 tid=0x00007ff74c001000 nid=0xac04b waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "DestroyJavaVM" #30 prio=5 os_prio=0 tid=0x00007ff nid=0xabd63 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "http-nio-8086-AsyncTimeout" #28 daemon prio=5 os_prio=0 tid=0x00007ff784dc3800 nid=0xabd84 waiting on condition [0x00007ff75028d000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1113) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-Acceptor-0" #27 daemon prio=5 os_prio=0 tid=0x00007ff784b29000 nid=0xabd83 runnable [0x00007ff75038e000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250) - locked <0x00000000de7a5c18> (a java.lang.Object) at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:446) at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:70) at org.apache.tomcat.util.net.Acceptor.run(Acceptor.java:95) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-ClientPoller-1" #26 daemon prio=5 os_prio=0 tid=0x00007ff784c3b000 nid=0xabd82 runnable [0x00007ff75048f000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000de905e98> (a sun.nio.ch.Util$3) - locked <0x00000000de905e88> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000de905d70> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:742) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-ClientPoller-0" #25 daemon prio=5 os_prio=0 tid=0x00007ff784c39000 nid=0xabd81 runnable [0x00007ff] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000de8f5570> (a sun.nio.ch.Util$3) - locked <0x00000000de8f5560> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000de8f5448> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:742) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-10" #24 daemon prio=5 os_prio=0 tid=0x00007ff784c37000 nid=0xabd80 waiting on condition [0x00007ff] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-9" #23 daemon prio=5 os_prio=0 tid=0x00007ff784c31000 nid=0xabd7f waiting on condition [0x00007ff] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-8" #22 daemon prio=5 os_prio=0 tid=0x00007ff784c2f000 nid=0xabd7e waiting on condition [0x00007ff] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-7" #21 daemon prio=5 os_prio=0 tid=0x00007ff784c2d000 nid=0xabd7d waiting on condition [0x00007ff] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-6" #20 daemon prio=5 os_prio=0 tid=0x00007ff784db9800 nid=0xabd7c waiting on condition [0x00007ff750a95000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-5" #19 daemon prio=5 os_prio=0 tid=0x00007ff784db7800 nid=0xabd7b waiting on condition [0x00007ff750b96000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-4" #18 daemon prio=5 os_prio=0 tid=0x00007ff784db6000 nid=0xabd7a waiting on condition [0x00007ff750c97000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-3" #17 daemon prio=5 os_prio=0 tid=0x00007ff784b34000 nid=0xabd79 waiting on condition [0x00007ff750d98000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-2" #16 daemon prio=5 os_prio=0 tid=0x00007ff784b33000 nid=0xabd78 waiting on condition [0x00007ff750e99000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8086-exec-1" #15 daemon prio=5 os_prio=0 tid=0x00007ff78481e000 nid=0xabd77 waiting on condition [0x00007ff750f9a000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000de7fa610> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "NioBlockingSelector.BlockPoller-1" #14 daemon prio=5 os_prio=0 tid=0x00007ff784c28800 nid=0xabd76 runnable [0x00007ff] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000de7a8860> (a sun.nio.ch.Util$3) - locked <0x00000000de7a87d8> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000de7a8410> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:298) Locked ownable synchronizers: - None "container-0" #13 prio=5 os_prio=0 tid=0x00007ff784f35000 nid=0xabd75 waiting on condition [0x00007ff7520ac000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.catalina.core.StandardServer.await(StandardServer.java:408) at org.springframework.boot.web.embedded.tomcat.TomcatWebServer$1.run(TomcatWebServer.java:181) Locked ownable synchronizers: - None "ContainerBackgroundProcessor[StandardEngine[Tomcat]]" #12 daemon prio=5 os_prio=0 tid=0x00007ff784f2a000 nid=0xabd74 waiting on condition [0x00007ff75372d000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1365) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "Service Thread" #8 daemon prio=9 os_prio=0 tid=0x00007ff7841b5000 nid=0xabd6f runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "C1 CompilerThread2" #7 daemon prio=9 os_prio=0 tid=0x00007ff nid=0xabd6e waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "C2 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007ff nid=0xabd6d waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007ff nid=0xabd6c waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007ff nid=0xabd6b runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007ff78414a800 nid=0xabd6a in Object.wait() [0x00007ff76c13c000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x0000000086932c90> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143) - locked <0x0000000086932c90> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209) Locked ownable synchronizers: - None "Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007ff nid=0xabd69 in Object.wait() [0x00007ff76c23d000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x0000000086932c60> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:502) at java.lang.ref.Reference.tryHandlePending(Reference.java:191) - locked <0x0000000086932c60> (a java.lang.ref.Reference$Lock) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153) Locked ownable synchronizers: - None "VM Thread" os_prio=0 tid=0x00007ff78413e800 nid=0xabd68 runnable "GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007ff78401f000 nid=0xabd64 runnable "GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007ff nid=0xabd65 runnable "GC task thread#2 (ParallelGC)" os_prio=0 tid=0x00007ff nid=0xabd66 runnable "GC task thread#3 (ParallelGC)" os_prio=0 tid=0x00007ff nid=0xabd67 runnable "VM Periodic Task Thread" os_prio=0 tid=0x00007ff7841b7800 nid=0xabd70 waiting on condition JNI global references: 1085 2.jstack -F [pid]
强制执行 thread dump，可在 Java 进程卡死（hung 住）时使用，此选项可能需要系统权限。
jstack -F 输出:
Attaching to process ID , please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 Deadlock Detection: No deadlocks found. Thread : (state = BLOCKED) Thread : (state = BLOCKED) Thread : (state = BLOCKED) - java.lang.Thread.sleep(long) @bci=0 (Compiled frame; information may be imprecise) - org.apache.coyote.AbstractProtocol$AsyncTimeout.run() @bci=10, line=1113 (Interpreted frame) - java.lang.Thread.run() @bci=11, line=748 (Interpreted frame) Thread : (state = IN_NATIVE) - sun.nio.ch.ServerSocketChannelImpl.accept0(java.io.FileDescriptor, java.io.FileDescriptor, java.net.InetSocketAddress[]) @bci=0 (Interpreted frame) - sun.nio.ch.ServerSocketChannelImpl.accept(java.io.FileDescriptor, java.io.FileDescriptor, java.net.InetSocketAddress[]) @bci=4, line=422 (Interpreted frame) - sun.nio.ch.ServerSocketChannelImpl.accept() @bci=130, line=250 (Interpreted frame) - org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept() @bci=4, line=446 (Interpreted frame) - org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept() @bci=1, line=70 (Interpreted frame) - org.apache.tomcat.util.net.Acceptor.run() @bci=98, line=95 (Interpreted frame) - java.lang.Thread.run() @bci=11, line=748 (Interpreted frame) 3.jstack -m [pid]
混合模式（mixed mode)，将 Java 帧和native 帧一起输出，此选项可能需要系统权限。
jstack -m 输出:
Attaching to process ID , please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.151-b12 Deadlock Detection: No deadlocks found. ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- 0x00007ff78cc4ecd6 do_futex_wait.constprop.1 + 0x36 ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- 0x00007ff78c55c0f7 epoll_wait + 0x57 ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- ----------------- 0x00007ff78c55c0f7 epoll_wait + 0x57 0x5a5f00f ???????? ----------------- ----------------- 0x00007ff78c55c0f7 epoll_wait + 0x57 0xf6c ???????? ----------------- ----------------- 0x00007ff78cc4fb07 __libc_accept + 0x47 ----------------- ----------------- ----------------- ----------------- 0x00007ff78cc4fb07 __libc_accept + 0x47 ----------------- ----------------- 0x00007ff78cc4766d __GI___pthread_timedjoin_ex + 0x18d 4.jstack -l [pid] | grep ‘java.lang.Thread.State’ | wc -l
统计现场个数
jstack -l | grep 'java.lang.Thread.State' | wc -l 输出:
[root@ashen-friede mnt]# jstack -l | grep 'java.lang.Thread.State' | wc -l 26 5.查看 linux 系统占用 cpu 较高的线程信息
5.1 top 查看cpu占用高进程
[root@ashen-friede mnt]# top top - 13:40:26 up 50 days, 2:36, 2 users, load average: 1.13, 1.07, 1.05 Tasks: 152 total, 1 running, 144 sleeping, 7 stopped, 0 zombie %Cpu(s): 16.5 us, 9.7 sy, 0.0 ni, 73.4 id, 0.0 wa, 0.3 hi, 0.0 si, 0.0 st MiB Mem : 7768.1 total, 637.5 free, 6313.4 used, 817.3 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 1186.9 avail Mem Unknown command - try 'h' for help PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND root 20 0 6032 1376 S 99.7 0.1 4380:57 python3.7 root 20 0 34172 3048 S 1.0 0.4 111:25.19 python3.7 23077 root 1 -19 65836 4 S 0.7 0.8 449:53.73 jfsmount root 10 -10 31432 8340 S 0.7 0.4 203:02.64 AliYunDun root 20 0 32568 4012 S 0.7 0.4 111:04.12 python3.7 17841 root 20 0 10268 S 0.3 3.7 48:38.10 java 18724 root 20 0 9388 S 0.3 4.2 96:47.51 java 20848 root 20 0 9724 S 0.3 3.7 129:23.67 java 21963 root 20 0 26828 6688 S 0.3 0.3 161:40.04 exe root 20 0 1.5g 9608 S 0.3 19.2 103:00.82 java root 20 0 0 0 0 I 0.3 0.0 0:03.53 kworker/3:3-events 1 root 20 0 6668 3732 S 0.0 0.1 0:55.32 systemd 2 root 20 0 0 0 0 S 0.0 0.0 0:01.20 kthreadd 3 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_gp 4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_par_gp 6 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/0:0H-events_highpri 9 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 mm_percpu_wq 10 root 20 0 0 0 0 S 0.0 0.0 0:04.15 ksoftirqd/0 11 root 20 0 0 0 0 I 0.0 0.0 23:15.05 rcu_sched 12 root rt 0 0 0 0 S 0.0 0.0 0:00.05 migration/0 13 root rt 0 0 0 0 S 0.0 0.0 0:00.03 watchdog/0 14 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0 15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1 16 root rt 0 0 0 0 S 0.0 0.0 0:02.14 watchdog/1 17 root rt 0 0 0 0 S 0.0 0.0 0:00.04 migration/1 18 root 20 0 0 0 0 S 0.0 0.0 0:02.63 ksoftirqd/1 20 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/1:0H-events_highpri 21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/2 22 root rt 0 0 0 0 S 0.0 0.0 0:02.21 watchdog/2 23 root rt 0 0 0 0 S 0.0 0.0 0:00.05 migration/2 24 root 20 0 0 0 0 S 0.0 0.0 0:03.36 ksoftirqd/2 26 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/2:0H-events_highpri 27 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/3 28 root rt 0 0 0 0 S 0.0 0.0 0:02.34 watchdog/3 29 root rt 0 0 0 0 S 0.0 0.0 0:00.05 migration/3 5.2 查看该进程下占用高 cpu 的线程
top -H -p 18038 输出:
[root@ashen-friede mnt]# top -H -p 18038 top - 13:48:40 up 50 days, 2:45, 2 users, load average: 0.61, 0.92, 0.99 Threads: 56 total, 0 running, 56 sleeping, 0 stopped, 0 zombie %Cpu(s): 1.6 us, 1.6 sy, 0.0 ni, 96.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st MiB Mem : 7768.1 total, 641.1 free, 6309.3 used, 817.6 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 1190.8 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 18038 root 20 0 9508 S 0.0 3.2 0:00.00 java 18040 root 20 0 9508 S 0.0 3.2 0:01.99 java 18041 root 20 0 9508 S 0.0 3.2 0:00.67 java 18042 root 20 0 9508 S 0.0 3.2 0:00.69 java 18043 root 20 0 9508 S 0.0 3.2 0:00.68 java 18044 root 20 0 9508 S 0.0 3.2 0:00.69 java 18045 root 20 0 9508 S 0.0 3.2 1:09.25 java 18046 root 20 0 9508 S 0.0 3.2 0:00.02 java 18047 root 20 0 9508 S 0.0 3.2 0:00.02 java 18048 root 20 0 9508 S 0.0 3.2 0:00.00 java 18049 root 20 0 9508 S 0.0 3.2 0:19.32 java 5.3 转换线程ID
printf "%x\n" 18040 输出:
[root@ashen-friede mnt]# printf "%x\n" 18040 4678 5.4 定位cpu占用线程
jstack 18038|grep 4678 -A 30 输出:
[root@ashen-friede mnt]# jstack 18038|grep 4678 -A 30 "Listener at 0.0.0.0/9867" #1 prio=5 os_prio=0 tid=0x00007f8f nid=0x4678 in Object.wait() [0x00007f8f4b] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x0000000086f65320> (a java.lang.Thread) at java.lang.Thread.join(Thread.java:1252) - locked <0x0000000086f65320> (a java.lang.Thread) at java.lang.Thread.join(Thread.java:1326) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.join(BPServiceActor.java:583) at org.apache.hadoop.hdfs.server.datanode.BPOfferService.join(BPOfferService.java:358) at org.apache.hadoop.hdfs.server.datanode.BlockPoolManager.joinAll(BlockPoolManager.java:143) at org.apache.hadoop.hdfs.server.datanode.DataNode.join(DataNode.java:2773) at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2909) at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2931) "VM Thread" os_prio=0 tid=0x00007f8f nid=0x467d runnable "GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007f8f nid=0x4679 runnable "GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007f8f4402b000 nid=0x467a runnable "GC task thread#2 (ParallelGC)" os_prio=0 tid=0x00007f8f4402d000 nid=0x467b runnable "GC task thread#3 (ParallelGC)" os_prio=0 tid=0x00007f8f4402e800 nid=0x467c runnable "VM Periodic Task Thread" os_prio=0 tid=0x00007f8f440d3800 nid=0x4685 waiting on condition JNI global references: 387 五. jcmd
Jcmd 综合了前面的几个命令
| 列 | 说明 |
|---|---|
| jcmd pid VM.uptime | 查看 JVM 的启动时长 |
| jcmd pid GC.class_histogram | 查看 JVM 的类信息，这个可以查看每个类的实例数量和占用空间大小。 |
| jcmd pid Thread.print | 查看 JVM 的Thread Dump |
| jcmd pid GC.heap_dump [file_name] | 查看 JVM 的Heap Dump,注意，如果只指定文件名，默认会生成在启动 JVM 的目录里。 |
| jcmd pid VM.system_properties | 查看 JVM 的属性信息 |
| jcmd pid VM.flags | 查看 JVM 的启动参数,注意，可以看到 -X 和 -XX 的参数信息 |
| jcmd pid VM.command_line | 查看 JVM 的启动命令行 |
| jcmd pid GC.run_finalization | 对 JVM 执行 java.lang.System.runFinalization(),尽量b别去调用这个对象的finalize方法。 |
| jcmd pid GC.run | 对 JVM 执行 java.lang.System.gc()，告诉垃圾收集器打算进行垃圾收集，而垃圾收集器进不进行收集是不确定的 |
| jcmd pid PerfCounter.print | 查看性能统计 |
六. jrunscript/jjs
1. 当 curl 命令用
jrunscript -e "cat('http://www.baidu.com')" jrunscript -e "cat('http://8.142.187.127:8096/api-exchange/v/general_api/search_api?id=4eb726fc742d4bbda6476da1af')" 2. 执行 js 脚本片段
jrunscript -e "print('hello, I am xiaohong')" 3. 执行 js 文件
function test(){
console.log("Hello JS") } test() jrunscript -l js -f /mnt/test.js 七. JVM 图形化工具
1. jconsole
在cmd命令行输入 jconsole 即可打开
- 本地 JVM 可以直接选择
- 远程 JVM 可以通过 JMX 方式连接
nohup java -Djava.rmi.server.hostname=172.29.38.64 -Dcom.sun.management.jmxremote=true -Dcom.sun.management.jmxremote.port=1507 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -jar api-exchange.jar & 8.142.187.127:1507
2. jvisualvm
3. jmc
4. idea 插件 VisualGC
免责声明：本站所有文章内容,图片，视频等均是来源于用户投稿和互联网及文摘转载整编而成，不代表本站观点，不承担相关法律责任。其著作权各归其原作者或其出版社所有。如发现本站有涉嫌抄袭侵权/违法违规的内容,侵犯到您的权益，请在线联系站长,一经查实,本站将立刻删除。 本文来自网络,若有侵权，请联系删除，如若转载，请注明出处：https://haidsoft.com/156363.html
