Linux general java program startup script code example

#!/bin/sh
#This script is a general script for starting a Java program under Linux. That is, it can be called as a self-starting service script.
#It can also be used as a standalone script to start a Java program.
#
#Author: tudaxia.com, Date: 2011/6/7
#
#Warning!!!: The stop part of this script uses the system kill command to forcibly terminate the specified Java program process.
#No conditional checks are done before killing the process. In some cases, such as when a program is writing to a file or database,
#May cause data loss or incomplete data. If you have to take this into account, you need to rewrite the script.
#Add a series of checks before executing the kill command.
#
#
###################################
#Environment variables and program execution parameters#These parameters need to be modified according to the actual environment and Java program name####################################
#JDK path JAVA_HOME="/usr/java/jdk"
 
#The system user used to start the execution program. For security reasons, it is recommended not to use the root account RUNNING_USER=root
 
#The directory where the Java program is located (the upper level directory of classes)
APP_HOME=/opt/tudaxia/test/WEB-INF
 
#The Java main program that needs to be started (main method class)
APP_MAINCLASS=com.tudaxia.test.TestMain
 
#Put together the complete classpath parameter, including all jars in the specified lib directory
CLASSPATH=$APP_HOME/classes
for i in "$APP_HOME"/lib/*.jar; do
  CLASSPATH="$CLASSPATH":"$i"
done
 
#java virtual machine startup parameters JAVA_OPTS="-ms512m -mx512m -Xmn256m -Djava.awt.headless=true -XX:MaxPermSize=128m"
 
###################################
#(Function) Determine whether the program has been started#
#illustrate:
#Use the JPS command and grep command combination that comes with JDK to accurately find the pid
#jps plus l parameter means displaying the full package path of java #Use awk to split out the pid ($1 part) and the Java program name ($2 part)
###################################
# Initialize psid variable (global)
psid=0
 
checkpid() {
  javaps=`$JAVA_HOME/bin/jps -l | grep $APP_MAINCLASS`
 
  if [ -n "$javaps" ]; then
   psid=`echo $javaps | awk '{print $1}'`
  else
   psid=0
  fi
}
 
###################################
#(Function) Start the program#
#illustrate:
#1. First call the checkpid function to refresh the $psid global variable#2. If the program has been started ($psid is not equal to 0), it will prompt that the program has been started#3. If the program has not been started, execute the startup command line#4. After the startup command is executed, call the checkpid function again#5. If the result of step 4 can confirm the pid of the program, print [OK], otherwise print [Failed]
#Note: echo -n means no line break after printing characters#Note: Usage of "nohup command>/dev/null 2>&1 &"####################################
start() {
  checkpid
 
  if [ $psid -ne 0 ]; then
   echo "================================="
   echo "warn: $APP_MAINCLASS already started! (pid=$psid)"
   echo "================================="
  else
   echo -n "Starting $APP_MAINCLASS ..."
   JAVA_CMD="nohup $JAVA_HOME/bin/java $JAVA_OPTS -classpath $CLASSPATH $APP_MAINCLASS >/dev/null 2>&1 &"
   su - $RUNNING_USER -c "$JAVA_CMD"
   checkpid
   if [ $psid -ne 0 ]; then
     echo "(pid=$psid) [OK]"
   else
     echo "[Failed]"
   fi
  fi
}
 
###################################
#(Function) Stop the program#
#illustrate:
#1. First call the checkpid function to refresh the $psid global variable#2. If the program has been started ($psid is not equal to 0), then start to stop it, otherwise, it will prompt that the program is not running#3. Use the kill -9 pid command to force kill the process#4. Execute the kill command line immediately and check the return value of the previous command: $?
#5. If the result of step 4, $?, is equal to 0, then print [OK], otherwise print [Failed]
#6. In order to prevent the Java program from being started multiple times, we add the process of repeatedly checking and killing the process (recursively calling stop).
#Note: echo -n means no line break after printing characters#Note: In shell programming, "$?" means the return value of the previous command or a function######################################
stop() {
  checkpid
 
  if [ $psid -ne 0 ]; then
   echo -n "Stopping $APP_MAINCLASS ...(pid=$psid) "
   su - $RUNNING_USER -c "kill -9 $psid"
   if [ $? -eq 0 ]; then
     echo "[OK]"
   else
     echo "[Failed]"
   fi
 
   checkpid
   if [ $psid -ne 0 ]; then
     stop
   fi
  else
   echo "================================="
   echo "warn: $APP_MAINCLASS is not running"
   echo "================================="
  fi
}
 
###################################
#(Function) Check program running status#
#illustrate:
#1. First call the checkpid function to refresh the $psid global variable. #2. If the program has been started ($psid is not equal to 0), it will prompt that it is running and indicate the pid
#3. Otherwise, it will prompt that the program is not running#####################################
status() {
  checkpid
 
  if [ $psid -ne 0 ]; then
   echo "$APP_MAINCLASS is running! (pid=$psid)"
  else
   echo "$APP_MAINCLASS is not running"
  fi
}
 
###################################
#(Function) Print system environment parameters#####################################
info() {
  echo "System Information:"
  echo "********************************"
  echo `head -n 1 /etc/issue`
  echo `uname -a`
  echo
  echo "JAVA_HOME=$JAVA_HOME"
  echo `$JAVA_HOME/bin/java -version`
  echo
  echo "APP_HOME=$APP_HOME"
  echo "APP_MAINCLASS=$APP_MAINCLASS"
  echo "********************************"
}
 
###################################
#Read the first parameter ($1) of the script and make a judgment#Parameter value range: {start|stop|restart|status|info}
#If the parameter is not within the specified range, print help information#####################################
case "$1" in
  'start')
   start
   ;;
  'stop')
   stop
   ;;
  'restart')
   stop
   start
   ;;
  'status')
   status
   ;;
  'info')
   info
   ;;
 *)
   echo "Usage: $0 {start|stop|restart|status|info}"
   exit 1
esac;