ThreadDump對於JVM診斷和調優是個好東西. 以前, 我們生成ThreadDump, 一般都需要另外連到服務器上的進程管理器才行, 不管是Ctrl+Break還是kill –3, 比較不方便. 有時候, 也許想遠程直接生成並檢查一下服務器的ThreadDump, 這個怎麼辦呢? 幸好我們有以下代碼可以做到:
util.threaddump.ThreadDumpBuilder.java
package util.threaddump;
import java.util.Map;
/**
* 使用 Java 遠程代碼生成 ThreadDump. 適用於 JDK 1.5+.
* 參考: {@link Thread#getStackTrace()}
* {@link Throwable#getStackTrace()}
* @see StackTraceElement
* @author [email protected]
* 轉載請注明出處: beansoft.blogjava.net
*/
public class ThreadDumpBuilder {
/**
* 生成並返回 Thread Dump.
* 轉載請注明出處: beansoft.blogjava.net
* @return
*/
public String build() {
StringBuilder output = new StringBuilder(1000);
for (Map.Entry stackTrace : Thread.getAllStackTraces().entrySet()) {
appendThreadStackTrace(output, (Thread) stackTrace.getKey(),
(StackTraceElement[]) stackTrace.getValue());
}
return output.toString();
}
/**
* 處理並輸出堆棧信息.
* @param output
* 輸出內容
* @param thread
* 線程
* @param stack
* 線程堆棧
*/
private void appendThreadStackTrace(StringBuilder output, Thread thread,
StackTraceElement[] stack) {
// 忽略當前線程的堆棧信息
if (thread.equals(Thread.currentThread())) {
return;
}
output.append(thread).append("\n");
for (StackTraceElement element : stack) {
output.append("\t").append(element).append("\n");
}
}
}
然後在一個JSP裡或者Servlet中任意調用即可:
<%=new ThreadDumpBuilder().build() %>
我用的 Oracle JRocket ReamTime 的JVM跑的空的Tomcat, 輸出內容如下:
Thread[(GC Main Thread),5,system]
Thread[Main Thread,5,main]
java.net.PlainSocketImpl.socketAccept(Native Method)
java.net.PlainSocketImpl.accept(PlainSocketImpl.java:384)
java.net.ServerSocket.implAccept(ServerSocket.java:453)
java.net.ServerSocket.accept(ServerSocket.java:421)
org.apache.catalina.core.StandardServer.await(StandardServer.java:389)
org.apache.catalina.startup.Catalina.await(Catalina.java:630)
org.apache.catalina.startup.Catalina.start(Catalina.java:590)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Thread[TP-Processor1,5,main]
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:485)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:658)
java.lang.Thread.run(Thread.java:619)
Thread[TP-Processor3,5,main]
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:485)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:658)
java.lang.Thread.run(Thread.java:619)
Thread[(VM Periodic Task),10,system]
Thread[ContainerBackgroundProcessor[StandardEngine[Catalina]],5,main]
java.lang.Thread.sleep(Native Method)
org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1579)
java.lang.Thread.run(Thread.java:619)
Thread[Finalizer,8,system]
java.lang.Thread.run(Thread.java:619)
Thread[TP-Processor2,5,main]
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:485)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:658)
java.lang.Thread.run(Thread.java:619)
Thread[Reference Handler,10,system]
java.lang.ref.Reference.waitForActivatedQueue(Native Method)
java.lang.ref.Reference.access$100(Reference.java:11)
java.lang.ref.Reference$ReferenceHandler.run(Reference.java:79)
Thread[(Code Generation Thread 1),5,system]
Thread[TP-Processor4,5,main]
java.net.PlainSocketImpl.socketAccept(Native Method)
java.net.PlainSocketImpl.accept(PlainSocketImpl.java:384)
java.net.ServerSocket.implAccept(ServerSocket.java:453)
java.net.ServerSocket.accept(ServerSocket.java:421)
org.apache.jk.common.ChannelSocket.accept(ChannelSocket.java:306)
org.apache.jk.common.ChannelSocket.acceptConnections(ChannelSocket.java:660)
org.apache.jk.common.ChannelSocket$SocketAcceptor.runIt(ChannelSocket.java:870)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:686)
java.lang.Thread.run(Thread.java:619)
Thread[http-8080-Acceptor-0,5,main]
java.net.PlainSocketImpl.socketAccept(Native Method)
java.net.PlainSocketImpl.accept(PlainSocketImpl.java:384)
java.net.ServerSocket.implAccept(ServerSocket.java:453)
java.net.ServerSocket.accept(ServerSocket.java:421)
org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:61)
org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:310)
java.lang.Thread.run(Thread.java:619)
Thread[(Signal Handler),5,system]
Thread[(Sensor Event Thread),5,system]
Thread[TP-Monitor,5,main]
java.lang.Object.wait(Native Method)
org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable.run(ThreadPool.java:561)
java.lang.Thread.run(Thread.java:619)
Thread[(Attach Listener),5,system]
Thread[(Code Optimization Thread 1),5,system]
對比用 Ctrl + Break 做出的GC, 顯然因為有安全性的限制, 輸出的日志信息比上面的方式詳細的多, 因此這仍然是推薦做法:
===== FULL THREAD DUMP ===============
Sun Aug 16 15:37:48 2009
BEA JRockit(R) R27.6.3-40_o-112056-1.6.0_11-20090318-2104-windows-ia32
"Main Thread" id=1 idx=0x4 tid=1760 prio=5 alive, in native
at java/net/PlainSocketImpl.socketAccept(Ljava/net/SocketImpl;)V(Native Method)
at java/net/PlainSocketImpl.accept(PlainSocketImpl.java:384)
^-- Holding lock: java/net/SocksSocketImpl@0x017CA398[biased lock]
at java/net/ServerSocket.implAccept(ServerSocket.java:453)
at java/net/ServerSocket.accept(ServerSocket.java:421)
at org/apache/catalina/core/StandardServer.await(StandardServer.java:389)
at org/apache/catalina/startup/Catalina.await(Catalina.java:630)
at org/apache/catalina/startup/Catalina.start(Catalina.java:590)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
at jrockit/vm/Reflect.invokeMethod(Ljava/lang/Object;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;(Native
Method)
at sun/reflect/NativeMethodAccessorImpl.invoke0(Ljava/lang/reflect/Method;Ljava/lang/Object;[Ljava/lang/Object;)Ljav
a/lang/Object;(Native Method)
at sun/reflect/NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun/reflect/DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java/lang/reflect/Method.invoke(Method.java:597)
at org/apache/catalina/startup/Bootstrap.start(Bootstrap.java:288)
at org/apache/catalina/startup/Bootstrap.main(Bootstrap.java:413)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"(Signal Handler)" id=2 idx=0x8 tid=1368 prio=5 alive, in native, daemon
"(GC Main Thread)" id=3 idx=0xc tid=1912 prio=5 alive, in native, native_waiting, daemon
"(GC Worker Thread 1)" id=? idx=0x10 tid=2760 prio=5 alive, in native, daemon
"(GC Worker Thread 2)" id=? idx=0x14 tid=1432 prio=5 alive, in native, daemon
"(Code Generation Thread 1)" id=4 idx=0x18 tid=2104 prio=5 alive, in native, native_waiting, daemon
"(Code Optimization Thread 1)" id=5 idx=0x1c tid=1136 prio=5 alive, in native, native_waiting, daemon
"(VM Periodic Task)" id=6 idx=0x20 tid=2184 prio=10 alive, in native, daemon
"(Attach Listener)" id=7 idx=0x24 tid=2464 prio=5 alive, in native, daemon
"Finalizer" id=8 idx=0x28 tid=2668 prio=8 alive, in native, native_waiting, daemon
at jrockit/memory/Finalizer.waitForFinalizees([Ljava/lang/Object;)I(Native Method)
at jrockit/memory/Finalizer.access$500(Finalizer.java:12)
at jrockit/memory/Finalizer$4.run(Finalizer.java:159)
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"Reference Handler" id=9 idx=0x2c tid=772 prio=10 alive, in native, native_waiting, daemon
at java/lang/ref/Reference.waitForActivatedQueue()Ljava/lang/ref/Reference;(Native Method)
at java/lang/ref/Reference.access$100(Reference.java:11)
at java/lang/ref/Reference$ReferenceHandler.run(Reference.java:79)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"(Sensor Event Thread)" id=10 idx=0x30 tid=280 prio=5 alive, in native, daemon
"ContainerBackgroundProcessor[StandardEngine[Catalina]]" id=12 idx=0x34 tid=3616 prio=5 alive, in native, sleeping, nati
ve_waiting, daemon
at java/lang/Thread.sleep(J)V(Native Method)
at org/apache/catalina/core/ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1579)
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"http-8080-Acceptor-0" id=13 idx=0x38 tid=2780 prio=5 alive, in native, daemon
at java/net/PlainSocketImpl.socketAccept(Ljava/net/SocketImpl;)V(Native Method)
at java/net/PlainSocketImpl.accept(PlainSocketImpl.java:384)
^-- Holding lock: java/net/SocksSocketImpl@0x031F98D0[biased lock]
at java/net/ServerSocket.implAccept(ServerSocket.java:453)
at java/net/ServerSocket.accept(ServerSocket.java:421)
at org/apache/tomcat/util/net/DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:61)
at org/apache/tomcat/util/net/JIoEndpoint$Acceptor.run(JIoEndpoint.java:310)
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"TP-Processor1" id=14 idx=0x3c tid=3184 prio=5 alive, in native, waiting, daemon
-- Waiting for notification on: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179EB28[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)
at java/lang/Object.wait(J)V(Native Method)
at java/lang/Object.wait(Object.java:485)
at org/apache/tomcat/util/threads/ThreadPool$ControlRunnable.run(ThreadPool.java:658)
^-- Lock released while waiting: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179EB28[fat lock]
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"TP-Processor2" id=15 idx=0x40 tid=2336 prio=5 alive, in native, waiting, daemon
-- Waiting for notification on: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179EF40[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)
at java/lang/Object.wait(J)V(Native Method)
at java/lang/Object.wait(Object.java:485)
at org/apache/tomcat/util/threads/ThreadPool$ControlRunnable.run(ThreadPool.java:658)
^-- Lock released while waiting: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179EF40[fat lock]
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"TP-Processor3" id=16 idx=0x44 tid=2644 prio=5 alive, in native, waiting, daemon
-- Waiting for notification on: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179F400[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)
at java/lang/Object.wait(J)V(Native Method)
at java/lang/Object.wait(Object.java:485)
at org/apache/tomcat/util/threads/ThreadPool$ControlRunnable.run(ThreadPool.java:658)
^-- Lock released while waiting: org/apache/tomcat/util/threads/ThreadPool$ControlRunnable@0x0179F400[fat lock]
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"TP-Processor4" id=17 idx=0x48 tid=1384 prio=5 alive, in native, daemon
at java/net/PlainSocketImpl.socketAccept(Ljava/net/SocketImpl;)V(Native Method)
at java/net/PlainSocketImpl.accept(PlainSocketImpl.java:384)
^-- Holding lock: java/net/SocksSocketImpl@0x0176E128[biased lock]
at java/net/ServerSocket.implAccept(ServerSocket.java:453)
at java/net/ServerSocket.accept(ServerSocket.java:421)
at org/apache/jk/common/ChannelSocket.accept(ChannelSocket.java:306)
at org/apache/jk/common/ChannelSocket.acceptConnections(ChannelSocket.java:660)
at org/apache/jk/common/ChannelSocket$SocketAcceptor.runIt(ChannelSocket.java:870)
at org/apache/tomcat/util/threads/ThreadPool$ControlRunnable.run(ThreadPool.java:686)
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"TP-Monitor" id=18 idx=0x4c tid=2788 prio=5 alive, in native, waiting, daemon
-- Waiting for notification on: org/apache/tomcat/util/threads/ThreadPool$MonitorRunnable@0x0179FBB0[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)
at java/lang/Object.wait(J)V(Native Method)
at org/apache/tomcat/util/threads/ThreadPool$MonitorRunnable.run(ThreadPool.java:561)
^-- Lock released while waiting: org/apache/tomcat/util/threads/ThreadPool$MonitorRunnable@0x0179FBB0[fat lock]
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
"http-8080-1" id=20 idx=0x50 tid=2192 prio=5 alive, in native, waiting, daemon
-- Waiting for notification on: org/apache/tomcat/util/net/JIoEndpoint$Worker@0x016649A8[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Method)
at java/lang/Object.wait(J)V(Native Method)
at java/lang/Object.wait(Object.java:485)
at org/apache/tomcat/util/net/JIoEndpoint$Worker.await(JIoEndpoint.java:416)
^-- Lock released while waiting: org/apache/tomcat/util/net/JIoEndpoint$Worker@0x016649A8[fat lock]
at org/apache/tomcat/util/net/JIoEndpoint$Worker.run(JIoEndpoint.java:442)
at java/lang/Thread.run(Thread.java:619)
at jrockit/vm/RNI.c2java(IIIII)V(Native Method)
-- end of trace
===== END OF THREAD DUMP ===============
參考資料:
1. Atlassian Confluence：http://www.atlassian.com/software/confluence/
3.0 管理控制台2. JDK的DEMOjdk1.5.0\demo\management\FullThreadDump
