一例Linux上没法中止tomcat分析及解决

在生产测试环境中，在使用脚本catalina.sh中止tomcat进程后失败，即时在catalina.sh脚本执行时加入-force参数也会失败，使用sh -x 分析catalina.sh脚本中止过程，将中止失败的地方抽取出来：

+ FORCE=1
+ '[' '!' -z '' ']'
+ /usr/java/jdk1.6.0_38/bin/java -server -Xms2048m -Xmx2048m -Xmn768m -XX:PermSize=128m -XX:MaxPermSize=256m -XX:+UseParallelOldGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/xrltest1/tomcat/dumpfile/heap.bin -Xloggc:/home/xrltest1/tomcat/logs/gc.log -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/home/xrltest1/tomcat/endorsed -classpath /home/xrltest1/tomcat/bin/bootstrap.jar -Dcatalina.base=/home/xrltest1/tomcat -Dcatalina.home=/home/xrltest1/tomcat -Djava.io.tmpdir=/home/xrltest1/tomcat/temp org.apache.catalina.startup.Bootstrap stop
2015-3-21 11:59:53 org.apache.catalina.startup.Catalina stopServer
严重: Catalina.stop: 
java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:529)
        at java.net.Socket.connect(Socket.java:478)
        at java.net.Socket.<init>(Socket.java:375)
        at java.net.Socket.<init>(Socket.java:189)
        at org.apache.catalina.startup.Catalina.stopServer(Catalina.java:422)
        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.stopServer(Bootstrap.java:338)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:416)
+ '[' '!' -z '' ']'
+ '[' 1 -eq 1 ']'
+ '[' -z '' ']'
+ echo 'Kill failed: $CATALINA_PID not set'
Kill failed: $CATALINA_PID not set

从中能够看到，首先是执行java命令失败，没有中止tomcat，而后执行-force模块的命令，可是却没有找到$CATALINA_PID设定的进程号，咱们先不去关注java执行stop命令为何报错，而是看看为何加了-force参数也不起做用了

为何没有$CATALINA_PID？接下来就带你们一探究竟

首先，咱们将涉及到$CATALINA_PID变量的代码所有提取出来：

第一处：

#如下这句判断设置的$CATALINA_PID变量若是不存在，则显示”Using CATALINA_PID:

$CATALINA_PID"，若是存在则不显示
  if [ ! -z "$CATALINA_PID" ]; then
    echo "Using CATALINA_PID:    $CATALINA_PID"
  fi
f

第二处：（涉及到start参数的模块内的$CATALINA_PID变量，只是提出来分析，其实不对stop模块有影响）

-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
  -Dcatalina.base="$CATALINA_BASE" \
  -Dcatalina.home="$CATALINA_HOME" \
  -Djava.io.tmpdir="$CATALINA_TMPDIR" \
  org.apache.catalina.startup.Bootstrap "$@" start \
  >> "$CATALINA_OUT" 2>&1 &
#从&能够看出启动的命令在后台启动
  fi
if [ ! -z "$CATALINA_PID" ]; then
#判断CATALINA_PID若是不是空字符，则将Shell最后运行的后台Process的PID 传给$CATALINA_PID
echo $! > "$CATALINA_PID"
#在使用命令运行进程至后台时，可使用$!抓取前面启动运行在后台进程的进程号
fi
fi
#上面语句是tomcat在启动时，会将$CATALINA_PID写入PID进程号

第三处：

if [ ! -z "$CATALINA_PID" ]; then
  #$CATALINA_PID文件不是非空
    if [ -f "$CATALINA_PID" ]; then
      if [ -s "$CATALINA_PID" ]; then
        kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
#kill -0 pid 不发送任何信号，可是系统会进行错误检查。
        if [ $? -gt 0 ]; then
          echo "PID file found but no matching process was found. Stop aborted."
          exit 1
        fi
      else
        echo "PID file is empty and has been ignored."
      fi
    else
      echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."
      exit 1
    fi
  fi

#若是发现$CATALINA_PID则发送一个模拟结束进程的型号，若是返回值为0，则正常，其余则异常，作退出操做

#从上面的sh -x输出的信息对应的是：'[‘ ‘!’ -z ” ‘]’ 能够看出$CATALINA_PID变量没有设定，因此这个判断直接就结束了，什么都没作

#下面的代码紧接着stop的正常中止代码下
  if [ ! -z "$CATALINA_PID" ]; then
  #若是$CATALINA_PID不为空
    if [ -f "$CATALINA_PID" ]; then
#并且仍是普通文件
      while [ $SLEEP -ge 0 ]; do
  #并且$SLEEP还大于0
        kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
#则测试下tomcat能不能被关闭
        if [ $? -gt 0 ]; then
#剩下的参数还有，则清空$CATALINA_PID
          rm -f "$CATALINA_PID" >/dev/null 2>&1
          if [ $? != 0 ]; then
            if [ -w "$CATALINA_PID" ]; then
              cat /dev/null > "$CATALINA_PID"
            else
              echo "Tomcat stopped but the PID file could not be removed or cleared."
            fi
          fi
          break
        fi
        if [ $SLEEP -gt 0 ]; then
          sleep 1
        fi
        if [ $SLEEP -eq 0 ]; then
          if [ $FORCE -eq 0 ]; then
            echo "Tomcat did not stop in time. PID file was not removed."
          fi
        fi
        SLEEP=`expr $SLEEP - 1 `
      done
    fi
  fi
  #上段语句主要是判断tomcat是否被关闭
  #核心语句仍是：kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
  #while语句作sleep使用，用于清空$CATALINA_PID
  #可是[ ! -z "$CATALINA_PID" ]致使这段语句什么都没作啊！！！！！

d

#这段代码就是涉及-force的核心代码了
  if [ $FORCE -eq 1 ]; then
    if [ -z "$CATALINA_PID" ]; then
      echo "Kill failed: \$CATALINA_PID not set"
    else
      if [ -f "$CATALINA_PID" ]; then
        PID=`cat "$CATALINA_PID"`
        echo "Killing Tomcat with the PID: $PID"
        kill -9 $PID
#强制执行的核心命令
        rm -f "$CATALINA_PID" >/dev/null 2>&1
        if [ $? != 0 ]; then
          echo "Tomcat was killed but the PID file could not be removed."
        fi
      fi
    fi
  fi
#从中就能够看出，sh -x输出的Kill failed: $CATALINA_PID not set是怎么来的

总结下，$CATALINA_PID在整个代码中的做用：

1.在tomcat启动时会写入$CATALINA_PID，可是假设咱们的环境是多tomcat项目或$CATALINA_PID为空

2.stop代码中，检查$CATALINA_PID是否为空字符，是的话什么都不作

3.sstop代码中，检查$CATALINA_PID是否为空字符，是的话什么都不作

4.force代码中，检查$CATALINA_PID是否为空字符，是的话就报错

也就是说只要没有保存中这个项目的PID，那么正常stop中止不了，-force也是没有用的。

那么该如何解决呢？直接给$CATALINA_PID付PID的值，那么看结果：

+ FORCE=1
+ '[' '!' -z 12031 ']'
+ '[' -f 12031 ']'
+ echo '$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted.'
$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted.

涉及到的代码：

if [ -f "$CATALINA_PID" ]; then
  if [ -s "$CATALINA_PID" ]; then
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
#kill -0 pid 不发送任何信号，可是系统会进行错误检查。
if [ $? -gt 0 ]; then
  echo "PID file found but no matching process was found. Stop aborted."
  exit 1
fi
  else
echo "PID file is empty and has been ignored."
  fi
else
  echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."
  exit 1
 #$CATALINA_PID不是个文件，因此很差意思，我退出了....

原来$CATALINA_PID还必须是个文件，那么咱们可不能够建这么一个文件呢？

在catalina.sh脚本的代码前，加入如下语句：

CATALINA_PID=/home/CATALINA_PID

若是tomcat启动时出现：

Existing PID file found during start.
Removing/clearing stale PID file.

说明生效了，可是若是项目中用了java.util.concurrent包里面的线程池，此方法无效，仍是不能关闭tomcat，关闭 tomcat时会出现Tomcat did not stop in time. PID file was not removed. To aid diagnostics a thread dump has been written to standard out，把线程池再改成spring管理便可