第四章：java虚拟机命令行工具

1：jps命令行进程状况工具      jps [options] [hostid]

C:\Users\lenovo>jps -l

13824 sun.tools.jps.Jps

14224 org.jetbrains.jps.cmdline.Launcher

8528 org.jetbrains.idea.maven.server.RemoteMavenServer

12660 org.jetbrains.jps.cmdline.Launcher

7316

11544

236 com.li.SpringBootLabApplication   //主类

2:jstat 用于监视虚拟机各种运行状态信息的命令行工具。包括类装载，内存，垃圾收集，JIT编译等数据

jstat [option vmid [interval [s|ms][count]]]

option 代表用户希望查询的虚拟机信息

例如每250毫秒查询一次进程236的垃圾回收信息，查询20次

3：jinfo 打印java配置信息

打印进程

jinfo 236的信息

C:\Users\lenovo>jinfo 236Attaching to process ID236, please wait...

Debugger attached successfully.

Server compiler detected.

JVM versionis 25.161-b12

Java System Properties:

java.runtime.name=Java(TM) SE Runtime Environment

java.vm.version= 25.161-b12

sun.boot.library.path= D:\software\jdk\jdk8\jdk1.8.0_161\jre\bin

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=sun.java.launcher=SUN_STANDARD

user.script=user.country=CN

user.dir=D:\software\github\github下载\laboratoryWeb

java.vm.specification.name=Java Virtual Machine Specification

PID= 236java.runtime.version= 1.8.0_161-b12

java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment

os.arch=amd64

java.endorsed.dirs= D:\software\jdk\jdk8\jdk1.8.0_161\jre\lib\endorsed

org.jboss.logging.provider=slf4j

line.separator=java.io.tmpdir=C:\Users\lenovo\AppData\Local\Temp\

java.vm.specification.vendor=Oracle Corporation

user.variant=os.name= Windows 10sun.jnu.encoding=GBK

java.library.path= D:\software\jdk\jdk8\jdk1.8.0_161\bin;C:\Users\lenovo\.gradle\caches\modules-2\files-2.1\org.ow2.asm\asm\5.0.3\dcc2193db20e19e1feca8b1240dbbc4e190824fa\asm-5.0.3.jar;D:\software\ideaj\ideaIC-2017.3.4.win\lib\idea_rt.jar

java.vm.specification.version= 1.8sun.arch.data.model= 64sun.java.command=com.li.SpringBootLabApplication

java.home= D:\software\jdk\jdk8\jdk1.8.0_161\jre

user.language=zh

java.specification.vendor=Oracle Corporation

awt.toolkit=sun.awt.windows.WToolkit

java.vm.info=mixed mode

java.version= 1.8.0_161

java.ext.dirs= D:\software\jdk\jdk8\jdk1.8.0_161\jre\lib\ext;C:\WINDOWS\Sun\Java\lib\ext

sun.boot.class.path = D:\software\jdk\jdk8\jdk1.8.0_161\jre\lib\resources.jar;D:\software\jdk\jdk8\jdk1.8.0_161\jre\classes

java.awt.headless= truejava.vendor=Oracle Corporation

catalina.base = C:\Users\lenovo\AppData\Local\Temp\tomcat.6690132104814217884.9002file.separator=\

java.vendor.url.bug= http://bugreport.sun.com/bugreport/

sun.io.unicode.encoding =UnicodeLittle

sun.cpu.endian=little

sun.desktop=windows

sun.cpu.isalist=amd64

VM Flags:

Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=134217728 -XX:MaxHeapSize=2122317824 -XX:MaxNewSize=707264512 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=44564480 -XX:OldSize=89653248 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:-UseLargePagesIndividualAllocation -XX:+UseParallelGC

Command line:-javaagent:D:\software\ideaj\ideaIC-2017.3.4.win\lib\idea_rt.jar=50372:D:\software\ideaj\ideaIC-2017.3.4.win\bin -Dfile.encoding=UTF-8

4：jmap： java内存映像工具

例如显示 java堆详细信息

jmap -heap 236

C:\Users\lenovo>jmap -heap 236Attaching to process ID236, please wait...

Debugger attached successfully.

Server compiler detected.

JVM versionis 25.161-b12using thread-local objectallocation.

Parallel GC with4thread(s)

Heap Configuration:

MinHeapFreeRatio= 0MaxHeapFreeRatio= 100MaxHeapSize= 2122317824 (2024.0MB)

NewSize= 44564480 (42.5MB)

MaxNewSize= 707264512 (674.5MB)

OldSize= 89653248 (85.5MB)

NewRatio= 2SurvivorRatio= 8MetaspaceSize= 21807104 (20.796875MB)

CompressedClassSpaceSize= 1073741824 (1024.0MB)

MaxMetaspaceSize= 17592186044415MB

G1HeapRegionSize= 0 (0.0MB)

Heap Usage:

PS Young Generation

Eden Space:

capacity= 195035136 (186.0MB)

used= 71367536 (68.06138610839844MB)

free= 123667600 (117.93861389160156MB)36.592143069031415%used

From Space:

capacity= 17825792 (17.0MB)

used= 17497968 (16.687362670898438MB)

free= 327824 (0.3126373291015625MB)98.16095688763787%used

To Space:

capacity= 14155776 (13.5MB)

used= 0 (0.0MB)

free= 14155776 (13.5MB)0.0%used

PS Old Generation

capacity= 112197632 (107.0MB)

used= 23719728 (22.620895385742188MB)

free= 88477904 (84.37910461425781MB)21.1410237249927%used24236 interned Strings occupying 2896624bytes.

C:\Users\lenovo>

5:jhat   虚拟机堆转储快照分析工具

6：jstack:    java堆栈跟踪工具

7: hsdis  JIT生成代码反汇编

可视化工具：

通过jdk/bin目录下的  jconsole.exe启动jconsole，将搜索出所有本地运行的虚拟机进程。

选择一个进程进行监控： 可查看各个状态的信息