本篇介绍一下如何在Linux下管理Java进程。由于在Linux下ps命令的强大，在linux下并不需要像Windows系统那样费力的区分不同的java进程。但是在Linux下，需要对进程进行这样的管理：一个商用的服务系统，需要提供的是24小时不间断的服务，但是由于各种原因，有可能会造成当前java进程对应的JVM的crash。因此，本篇介绍如何写一段shell脚本方便的启动、停止、守护一个java进程。
首先，这段shell应该有start和stop的功能。如何stop当前我想停止的进程在Linux下有很多方法，我用的方法是，启动时将进程对应的process id记录到一个文件中，在停止这个进程时，从文件中读取process id进行kill。同时，做一个crontab，不停在系统中查找文件中的process id对应的进程是否存在，如果不存在，重新启动该进程。
启动和停止脚本：ctrl.sh
Shell代码
#!/bin/sh # # start/stop the Service # # do some init here # case "$1" in 'restart') # first Stopping the Service PID=`sed -n 1p pidfile` #get pid from file if [ ! -z "$PID" ] ; then echo "Stopping the Service, begin killing ${PID}" kill ${PID} >/dev/null 2>&1 sleep 2 fi # second Starting the Service if [ some condition here ]; then echo "Starting the Service" java -classpath some_class_path_here -jar helloworld.jar & echo $! > pidfile #record process id to file fi ;; 'stop') # Stopping the Service PID=`sed -n 1p pidfile` #get pid from pidfile if [ ! -z "$PID" ] ; then echo "Stopping the Service, begin killing ${PID}" kill ${PID} >/dev/null 2>&1 fi ;; *) echo "Unmarkable usage: $0 {restart|stop}" ;; esac #!/bin/sh # # start/stop the Service # # do some init here # case "$1" in 'restart') # first Stopping the Service PID=`sed -n 1p pidfile` #get pid from file if [ ! -z "$PID" ] ; then echo "Stopping the Service, begin killing ${PID}" kill ${PID} >/dev/null 2>&1 sleep 2 fi # second Starting the Service if [ some condition here ]; then echo "Starting the Service" java -classpath some_class_path_here -jar helloworld.jar & echo $! > pidfile #record process id to file fi ;; 'stop') # Stopping the Service PID=`sed -n 1p pidfile` #get pid from pidfile if [ ! -z "$PID" ] ; then echo "Stopping the Service, begin killing ${PID}" kill ${PID} >/dev/null 2>&1 fi ;; *) echo "Unmarkable usage: $0 {restart|stop}" ;; esac然后再做一个crontab需要执行的脚本：crntb.sh