基本概念
有些时候我们需要查看下jvm中的线程执行情况，比如，发现服务器的CPU的负载突然增高了、出现了死锁、死循环等，我们该如何分析呢？
由于程序是正常运行的，没有任何的输出，从日志方面也看不出什么问题，所以就需要看下jvm的内部线程的执行情况，然后再进行分析查找出原因。
这个时候，就需要借助于jstack命令了，jstack的作用是将正在运行的jvm的线程情况进行快照，并且打印出来。
jstack是jdk自带的线程堆栈分析工具，使用该命令可以查看或导出 java 应用程序中线程堆栈信息。
jstack用于生成java虚拟机当前时刻的线程快照。线程快照是当前java虚拟机内每一条线程正在执行的方法堆栈的集合，生成线程快照的主要目的是定位线程出现长时间停顿的原因，如线程间死锁、死循环、请求外部资源导致的长时间等待等。 线程出现停顿的时候通过jstack来查看各个线程的调用堆栈，就可以知道没有响应的线程到底在后台做什么事情，或者等待什么资源。 如果java程序崩溃生成core文件，jstack工具可以用来获得core文件的java stack和native stack的信息，从而可以轻松地知道java程序是如何崩溃和在程序何处发生问题。另外，jstack工具还可以附属到正在运行的java程序中，看到当时运行的java程序的java stack和native stack的信息, 如果现在运行的java程序呈现hung的状态，jstack是非常有用的。
用法：
jstack [ options ] pid
pid：Java进程的ID，可以通过jps命令查询到。
jstack [ options ] executable core
executable： 产生core dump的Java可执行程序 core：要打印的堆栈跟踪的核心文件
jstack [ options ] [ server-id@ ] remote-hostname-or-IP
server-id：当多个DEBUG服务器在同一远程主机上运行时，可使用的可选唯一ID。 remote-hostname-or-IP：远程DEBUG的服务器主机名或IP地址
options 参数说明
- -F
当 jstack [-l] pid 没有响应时，强制打印一个堆栈转储。
- -l
打印关于锁的其他信息，比如拥有的java.util.concurrent ownable同步器的列表。
- -m
打印包含Java和本机C/ C 帧的混合模式堆栈跟踪。
- -h
打印帮助信息
- -help
打印帮助信息
代码语言：javascript复制[root@fsd bin]# jstack 2203
Full thread dump Java HotSpot(TM) 64‐Bit Server VM (25.141‐b15 mixed mode):
"Attach Listener" #24 daemon prio=9 os_prio=0 tid=0x00007fabb4001000 nid=0x906 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"http‐bio‐8080‐exec‐5" #23 daemon prio=5 os_prio=0 tid=0x00007fabb057c000 nid=0x8e1 waiting on condition [0x00007fabd05b8000]
java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method)
‐ parking to wait for <0x00000000f8508360> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awa it(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:44 2)
at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1 074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java
:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.jav a:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread
.java:61)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐exec‐4" #22 daemon prio=5 os_prio=0 tid=0x00007fab9c113800
nid=0x8e0 waiting on condition [0x00007fabd06b9000] java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
‐ parking to wait for <0x00000000f8508360> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awa it(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:44 2)
at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1 074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java
:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.jav a:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread
.java:61)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐exec‐3" #21 daemon prio=5 os_prio=0 tid=0x0000000001aeb800 nid=0x8df waiting on condition [0x00007fabd09ba000]
java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method)
‐ parking to wait for <0x00000000f8508360> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awa it(AbstractQueuedSynchronizer.java:2039)
at
java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:44 2)
at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1 074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java
:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.jav a:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread
.java:61)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐exec‐2" #20 daemon prio=5 os_prio=0 tid=0x0000000001aea000 nid=0x8de waiting on condition [0x00007fabd0abb000]
java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method)
‐ parking to wait for <0x00000000f8508360> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awa it(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:44 2)
at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1 074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java
:1134)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.jav a:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread
.java:61)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐exec‐1" #19 daemon prio=5 os_prio=0 tid=0x0000000001ae8800 nid=0x8dd waiting on condition [0x00007fabd0bbc000]
java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method)
‐ parking to wait for <0x00000000f8508360> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awa it(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:44 2)
at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1 074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java
:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.jav a:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread
.java:61)
at java.lang.Thread.run(Thread.java:748)
"ajp‐bio‐8009‐AsyncTimeout" #17 daemon prio=5 os_prio=0 tid=0x00007fabe8128000 nid=0x8d0 waiting on condition [0x00007fabd0ece000]
java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method)
at org.apache.tomcat.util.net.JIoEndpoint$AsyncTimeout.run(JIoEndpoint.java: 152)
at java.lang.Thread.run(Thread.java:748)
"ajp‐bio‐8009‐Acceptor‐0" #16 daemon prio=5 os_prio=0 tid=0x00007fabe82d4000 nid=0x8cf runnable [0x00007fabd0fcf000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method) at
java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409) at java.net.ServerSocket.implAccept(ServerSocket.java:545)
at java.net.ServerSocket.accept(ServerSocket.java:513) at
org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(Defaul tServerSocketFactory.java:60)
at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:220)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐AsyncTimeout" #15 daemon prio=5 os_prio=0 tid=0x00007fabe82d1800 nid=0x8ce waiting on condition [0x00007fabd10d0000]
java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method)
at org.apache.tomcat.util.net.JIoEndpoint$AsyncTimeout.run(JIoEndpoint.java: 152)
at java.lang.Thread.run(Thread.java:748)
"http‐bio‐8080‐Acceptor‐0" #14 daemon prio=5 os_prio=0 tid=0x00007fabe82d0000 nid=0x8cd runnable [0x00007fabd11d1000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method) at
java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409) at java.net.ServerSocket.implAccept(ServerSocket.java:545)
at java.net.ServerSocket.accept(ServerSocket.java:513)
at
org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(Defaul tServerSocketFactory.java:60)
at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:220)
at java.lang.Thread.run(Thread.java:748)
"ContainerBackgroundProcessor[StandardEngine[Catalina]]" #13 daemon prio=5 os_prio=0 tid=0x00007fabe82ce000 nid=0x8cc waiting on condition [0x00007fabd12d2000]
java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(C ontainerBase.java:1513)
at java.lang.Thread.run(Thread.java:748)
"GC Daemon" #10 daemon prio=2 os_prio=0 tid=0x00007fabe83b4000 nid=0x8b3 in Object.wait() [0x00007fabd1c2f000]
java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method)
‐ waiting on <0x00000000e315c2d0> (a sun.misc.GC$LatencyLock) at sun.misc.GC$Daemon.run(GC.java:117)
‐ locked <0x00000000e315c2d0> (a sun.misc.GC$LatencyLock)
"Service Thread" #7 daemon prio=9 os_prio=0 tid=0x00007fabe80c3800 nid=0x8a5 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"C1 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007fabe80b6800 nid=0x8a4 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007fabe80b3800 nid=0x8a3 waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007fabe80b2000 nid=0x8a2 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007fabe807f000 nid=0x8a1
in Object.wait() [0x00007fabd2a67000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method)
‐ waiting on <0x00000000e3162918> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
‐ locked <0x00000000e3162918> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)
"Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007fabe807a800 nid=0x8a0 in Object.wait() [0x00007fabd2b68000]
java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method)
‐ waiting on <0x00000000e3162958> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:502)
at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
‐ locked <0x00000000e3162958> (a java.lang.ref.Reference$Lock)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
"main" #1 prio=5 os_prio=0 tid=0x00007fabe8009000 nid=0x89c runnable [0x00007fabed210000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method) at
java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409) at java.net.ServerSocket.implAccept(ServerSocket.java:545)
at java.net.ServerSocket.accept(ServerSocket.java:513) at
org.apache.catalina.core.StandardServer.await(StandardServer.java:453) at org.apache.catalina.startup.Catalina.await(Catalina.java:777) at org.apache.catalina.startup.Catalina.start(Catalina.java:723) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java
:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorI mpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321)本文内容到此结束了， 如有收获欢迎点赞
