tomcat关不掉的原因

tomcat/bin 目录下的catalina.sh是比较常用的shell

Shell代码  
1.#启动tomcat   
2../catalina.sh start     
3.  
4.#关闭tomcat   
5../catalina.sh stop    
#启动tomcat
./catalina.sh start  

#关闭tomcat
./catalina.sh stop  

往往一个工程，开发一段时间后，会发现./catalina.sh stop关闭不了tomcat，而必须使用kill -9 <pid> 这样的强制命令去

杀死tomcat，这么做当然可以，但是手法不是那么的优雅



在tomat未被./catalina stop关闭的情况下，导致误以为tomcat已经关闭成功的哥们 会在更新完代码后，./catalina start一下，于是在服务器中就产生了2个tomcat的实例，log混乱，不知所措，ps 一看，大吃一惊，而后每次都用kill -9 <pid> 才放心。





其实不用那样，一般关闭不了的情况，是由于程序员自己在tomcat中开启了新的线程，而且未设置成daemon，造成的主线程不能退出.



怎么发现工程里到底哪里开启的新的非守护线程呢，其实jdk提供了jstack工具，可以帮助我们分析



查看方法很简单

$JAVA_HOME/bin/jstack  <pid>

pid是指进程ID， 用ps -ef|grep tomcat 就可以查看到：

Shell代码  
1.[root@localhost bin]# ps -ef|grep tomcat   
2.root      1513     1  2 23:41 pts/1    00:00:01 /usr/local/share/java/jdk1.6.0_25/bin/java -Djava.util.logging.config.file=/opt/apache-tomcat-6.0.32/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/apache-tomcat-6.0.32/endorsed -classpath /opt/apache-tomcat-6.0.32/bin/bootstrap.jar -Dcatalina.base=/opt/apache-tomcat-6.0.32 -Dcatalina.home=/opt/apache-tomcat-6.0.32 -Djava.io.tmpdir=/opt/apache-tomcat-6.0.32/temp org.apache.catalina.startup.Bootstrap start   
3.root      1544  1462  0 23:42 pts/1    00:00:00 grep --color=auto tomcat  
[root@localhost bin]# ps -ef|grep tomcat
root      1513     1  2 23:41 pts/1    00:00:01 /usr/local/share/java/jdk1.6.0_25/bin/java -Djava.util.logging.config.file=/opt/apache-tomcat-6.0.32/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/apache-tomcat-6.0.32/endorsed -classpath /opt/apache-tomcat-6.0.32/bin/bootstrap.jar -Dcatalina.base=/opt/apache-tomcat-6.0.32 -Dcatalina.home=/opt/apache-tomcat-6.0.32 -Djava.io.tmpdir=/opt/apache-tomcat-6.0.32/temp org.apache.catalina.startup.Bootstrap start
root      1544  1462  0 23:42 pts/1    00:00:00 grep --color=auto tomcat  
 

这里看到的进程ID是 1513



调用jstack查看:

Shell代码  
1.[root@localhost bin]# jstack 1513          
2.2011-07-12 23:44:00  
3.Full thread dump Java HotSpot(TM) Client VM (20.0-b11 mixed mode, sharing):   
4.  
5."Attach Listener" daemon prio=10 tid=0xb41d7c00 nid=0x606 waiting on condition [0x00000000]   
6.   java.lang.Thread.State: RUNNABLE   
7.  
8."TP-Monitor" daemon prio=10 tid=0xb41d6400 nid=0x5fa in Object.wait() [0xb3e0b000]   
9.   java.lang.Thread.State: TIMED_WAITING (on object monitor)   
10.        at java.lang.Object.wait(Native Method)   
11.        - waiting on <0x87143720> (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)   
12.        at org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable.run(ThreadPool.java:565)   
13.        - locked <0x87143720> (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)   
14.        at java.lang.Thread.run(Thread.java:662)   
15.  
16."TP-Processor4" daemon prio=10 tid=0xb41d4c00 nid=0x5f9 runnable [0xb3e5c000]   
17.   java.lang.Thread.State: RUNNABLE   
18.        at java.net.PlainSocketImpl.socketAccept(Native Method)   
19.        at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:408)   
20.        - locked <0x87124770> (a java.net.SocksSocketImpl)   
21.        at java.net.ServerSocket.implAccept(ServerSocket.java:462)   
22.        at java.net.ServerSocket.accept(ServerSocket.java:430)   
23.        at org.apache.jk.common.ChannelSocket.accept(ChannelSocket.java:311)   
24.        at org.apache.jk.common.ChannelSocket.acceptConnections(ChannelSocket.java:668)   
25.        at org.apache.jk.common.ChannelSocket$SocketAcceptor.runIt(ChannelSocket.java:879)   
26.        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)   
27.        at java.lang.Thread.run(Thread.java:662)  
[root@localhost bin]# jstack 1513       
2011-07-12 23:44:00
Full thread dump Java HotSpot(TM) Client VM (20.0-b11 mixed mode, sharing):

"Attach Listener" daemon prio=10 tid=0xb41d7c00 nid=0x606 waiting on condition [0x00000000]
   java.lang.Thread.State: RUNNABLE

"TP-Monitor" daemon prio=10 tid=0xb41d6400 nid=0x5fa in Object.wait() [0xb3e0b000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x87143720> (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)
        at org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable.run(ThreadPool.java:565)
        - locked <0x87143720> (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)
        at java.lang.Thread.run(Thread.java:662)

"TP-Processor4" daemon prio=10 tid=0xb41d4c00 nid=0x5f9 runnable [0xb3e5c000]
   java.lang.Thread.State: RUNNABLE
        at java.net.PlainSocketImpl.socketAccept(Native Method)
        at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:408)
        - locked <0x87124770> (a java.net.SocksSocketImpl)
        at java.net.ServerSocket.implAccept(ServerSocket.java:462)
        at java.net.ServerSocket.accept(ServerSocket.java:430)
        at org.apache.jk.common.ChannelSocket.accept(ChannelSocket.java:311)
        at org.apache.jk.common.ChannelSocket.acceptConnections(ChannelSocket.java:668)
        at org.apache.jk.common.ChannelSocket$SocketAcceptor.runIt(ChannelSocket.java:879)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
        at java.lang.Thread.run(Thread.java:662)  

其中看到"Attach Listener" daemon prio=10 tid=0xb41d7c00 nid=0x606 waiting on condition [0x00000000]

   java.lang.Thread.State: RUNNABLE

这行，最前变的"Attach Listener" 是线程名， 紧跟其后的 daemon是线程的守护状态，


其中主线程不是daemon的，所以是这样：

"main" prio=10 tid=0xb6d05000 nid=0x5ea runnable [0xb6ee9000]

   java.lang.Thread.State: RUNNABLE

        at java.net.PlainSocketImpl.socketAccept(Native Method)

        at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:408)

        - locked <0x871644a8> (a java.net.SocksSocketImpl)

        at java.net.ServerSocket.implAccept(ServerSocket.java:462)

        at java.net.ServerSocket.accept(ServerSocket.java:430)

        at org.apache.catalina.core.StandardServer.await(StandardServer.java:431)

        at org.apache.catalina.startup.Catalina.await(Catalina.java:676)

        at org.apache.catalina.startup.Catalina.start(Catalina.java:628)

        at sun.reflect.NativeMethodAccessorImpl.invoke0(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:289)

        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

在"main" 后没有daemon，看到这样的线程状态，顺藤摸瓜，找到对应new Thread的地方setDaemon(true)就可以，痛痛快快的./catalina stop了 ：）