Tomcat启动脚本catalina.sh---解读

(本文转自http://blog.chinaunix.net/space.php?uid=7930780&do=blog&id=2036912)
                         

Tomcat启动脚本catalina.sh 

1 - 概述

脚本catalina.sh用于启动和关闭tomcat服务器，是最关键的脚本
另外的脚本startup.sh和shutdown.sh都是使用不同的参数调用了该脚本
该脚本的使用方法如下（引自该脚本本身）：

  echo "Usage: catalina.sh ( commands ... )"
  echo "commands:"
  echo "  debug             Start Catalina in a debugger"
  echo "  debug -security   Debug Catalina with a security manager"
  echo "  embedded          Start Catalina in embedded mode"
  echo "  jpda start        Start Catalina under JPDA debugger"
  echo "  run               Start Catalina in the current window"
  echo "  run -security     Start in the current window with security manager"
  echo "  start             Start Catalina in a separate window"
  echo "  start -security   Start in a separate window with security manager"
  echo "  stop              Stop Catalina"

2 - 脚本分析

#!/bin/sh

 # ============================================================= # 该脚本设置正确的环境变量和系统信息，然后启动或者停止tomcat server # 具体的操作是： # 使用命令行参数作为args的实参，调用org.apache.catalina.startup.Bootstrap.main(String[]) # ============================================================== 
 # ----------------------------------------------------------------------------- # Start/Stop Script for the CATALINA Server # # Environment Variable Prequisites # # CATALINA_HOME May point at your Catalina "build" directory. # # CATALINA_BASE (Optional) Base directory for resolving dynamic portions # of a Catalina installation. If not present, resolves to # the same directory that CATALINA_HOME points to. # # CATALINA_OPTS (Optional) Java runtime options used when the "start", # "stop", or "run" command is executed. # # CATALINA_TMPDIR (Optional) Directory path location of temporary directory # the JVM should use (java.io.tmpdir). Defaults to # $CATALINA_BASE/temp. # # JAVA_HOME Must point at your Java Development Kit installation. # # JAVA_OPTS (Optional) Java runtime options used when the "start", # "stop", or "run" command is executed. # # JPDA_TRANSPORT (Optional) JPDA transport used when the "jpda start" # command is executed. The default is "dt_socket". # # JPDA_ADDRESS (Optional) Java runtime options used when the "jpda start" # command is executed. The default is 8000. # # JSSE_HOME (Optional) May point at your Java Secure Sockets Extension # (JSSE) installation, whose JAR files will be added to the # system class path used to start Tomcat. # # CATALINA_PID (Optional) Path of the file which should contains the pid # of catalina startup java process, when start (fork) is used # ----------------------------------------------------------------------------- 

 # OS specific support. $var _must_ be set to either true or false. 
cygwin=false
case "`uname`" in
CYGWIN*) cygwin=true;;
esac

 # PRG是被执行的脚本的名称，可以认为PRG=="catalina.sh"，也可能是某个符号链，指向该脚本。 
PRG="$0"

 # 处理了一下PRG，等循环跳出之后PRG成为 ???? 
while [ -h "$PRG" ]; do
  ls=`ls -ld "$PRG"`
  link=`expr "$ls" : '.*-> \(.*\)$'`
  if expr "$link" : '.*/.*' > /dev/null; then
    PRG="$link"
  else
    PRG=`dirname "$PRG"`/"$link"
  fi
done


 # PRGDIR是PRG的目录路径名称 
PRGDIR=`dirname "$PRG"`

 # 执行$CATALINA_HOME/BIN/setenv.sh来设置环境变量 # [ -r filename ] 是判断是否文件存在且可读 
CATALINA_HOME=`cd "$PRGDIR/.." ; pwd`
if [ -r "$CATALINA_HOME"/bin/setenv.sh ]; then
  . "$CATALINA_HOME"/bin/setenv.sh
fi


 # For Cygwin, 确保所有的路径名都符合UNIX格式 
if $cygwin; then
  [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
  [ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"`
  [ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"`
  [ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
  [ -n "$JSSE_HOME" ] && JSSE_HOME=`cygpath --path --unix "$JSSE_HOME"`
fi

 # 设置用来初始化SystemClassLoader的CLASSPATH变量：通过执行脚本setclasspath.sh完成 # 注意：脚本setclasspath.sh改变了原来的$CLASSPATH变量，而把它设为： # CLASSPATH=$CATALINA_HOME/bin/bootstrap.jar:$JAVA_HOME/lib/tools.jar # 其中bootstrap.jar是package org.apache.catalina.startup的打包文件， # 含有启动方法org.apache.catalina.startup.Bootstrap.main(String[] args) # tools.jar含有javac编译器，用来把jsp文件编译成为servlet class 
if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then
  BASEDIR="$CATALINA_HOME"
  . "$CATALINA_HOME"/bin/setclasspath.sh
else
  echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh"
  echo "This file is needed to run this program"
  exit 1
fi

 # 在CLASSPATH环境变量后面补上一些JAR文件 # [ -n string ] 判断字符串是否长度非0；[ -z string ] 判断字符串是否长度为0 # 它们可以用来判断是否某个环境变量已经被设置 
if [ -n "$JSSE_HOME" ]; then
  CLASSPATH="$CLASSPATH":"$JSSE_HOME"/lib/jcert.jar:"$JSSE_HOME"/lib/jnet.jar:"$JSSE_HOME"/lib/jsse.jar
fi
CLASSPATH="$CLASSPATH":"$CATALINA_HOME"/bin/bootstrap.jar


 # 指定CATALINA_BASE变量 # 如果CATALINA_BASE没有值，就让CATALINA_BASE=$CATALINA_HOME 

if [ -z "$CATALINA_BASE" ] ; then
  CATALINA_BASE="$CATALINA_HOME"
fi


 # 指定CATALINA_TMPDIR变量 # 如果CATALINA_TMPDIR没有值，就让CATALINA_TMPDIR=$CATALINA_BASE/temp 
if [ -z "$CATALINA_TMPDIR" ] ; then
  # Define the java.io.tmpdir to use for Catalina
  CATALINA_TMPDIR="$CATALINA_BASE"/temp
fi

 # For Cygwin, 在执行java程序前把路径名转换成WINDOWS格式 
if $cygwin; then
  JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
  CATALINA_HOME=`cygpath --path --windows "$CATALINA_HOME"`
  CATALINA_BASE=`cygpath --path --windows "$CATALINA_BASE"`
  CATALINA_TMPDIR=`cygpath --path --windows "$CATALINA_TMPDIR"`
  CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
  JSSE_HOME=`cygpath --path --windows "$JSSE_HOME"`
fi


 # 显示信息，然后执行命令 echo "Using CATALINA_BASE: $CATALINA_BASE" echo "Using CATALINA_HOME: $CATALINA_HOME" echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR" echo "Using JAVA_HOME: $JAVA_HOME" 

 # ......当执行catalina.sh的参数是jpda的时候...... 
if [ "$1" = "jpda" ] ; then
  if [ -z "$JPDA_TRANSPORT" ]; then
    JPDA_TRANSPORT="dt_socket"
  fi
  if [ -z "$JPDA_ADDRESS" ]; then
    JPDA_ADDRESS="8000"
  fi
  if [ -z "$JPDA_OPTS" ]; then
    JPDA_OPTS="-Xdebug -Xrunjdwp:transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=n"
  fi
  CATALINA_OPTS="$CATALINA_OPTS $JPDA_OPTS"
  shift
fi


 # ......当执行catalina.sh的参数是debug的时候...... 
if [ "$1" = "debug" ] ; then
  shift
  if [ "$1" = "-security" ] ; then
    echo "Using Security Manager"
    shift
    exec "$_RUNJDB" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
      -sourcepath "$CATALINA_HOME"/../../jakarta-tomcat-4.0/catalina/src/share \
      -Djava.security.manager \
      -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
      -Dcatalina.base="$CATALINA_BASE" \
      -Dcatalina.home="$CATALINA_HOME" \
      -Djava.io.tmpdir="$CATALINA_TMPDIR" \
      org.apache.catalina.startup.Bootstrap "$@" start
  else
    exec "$_RUNJDB" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
      -sourcepath "$CATALINA_HOME"/../../jakarta-tomcat-4.0/catalina/src/share \
      -Dcatalina.base="$CATALINA_BASE" \
      -Dcatalina.home="$CATALINA_HOME" \
      -Djava.io.tmpdir="$CATALINA_TMPDIR" \
      org.apache.catalina.startup.Bootstrap "$@" start
  fi


 # ......当执行catalina.sh的参数是embedded的时候...... 
elif [ "$1" = "embedded" ] ; then
  shift
  echo "Embedded Classpath: $CLASSPATH"
  exec "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
    -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
    -Dcatalina.base="$CATALINA_BASE" \
    -Dcatalina.home="$CATALINA_HOME" \
    -Djava.io.tmpdir="$CATALINA_TMPDIR" \
    org.apache.catalina.startup.Embedded "$@"


 # +----------------------------------------------------+ # | ......当执行catalina.sh的参数是run的时候...... | # | 在当前窗口中启动tomcat服务器！！！ | # +----------------------------------------------------+ 
elif [ "$1" = "run" ]; then
 # 把参数run去掉 
  shift
  
 # 如果参数是run -security，则启动Security Manager 
  if [ "$1" = "-security" ] ; then
    echo "Using Security Manager"
    shift
    exec "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
      -Djava.security.manager \
      -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
      -Dcatalina.base="$CATALINA_BASE" \
      -Dcatalina.home="$CATALINA_HOME" \
      -Djava.io.tmpdir="$CATALINA_TMPDIR" \
      org.apache.catalina.startup.Bootstrap "$@" start
      
 # 如果参数是孤单的run，则在本窗口中启动tomcat服务器 # 在本窗口中启动的方法是使用exec，让当前进程fork一个新进程来启动tomcat，当前进程是tomcat的父进程 # 启动tomcat的类是org.apache.catalina.startup.Bootstrap.main("start"); 
  else
    exec "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
      -Dcatalina.base="$CATALINA_BASE" \
      -Dcatalina.home="$CATALINA_HOME" \
      -Djava.io.tmpdir="$CATALINA_TMPDIR" \
      org.apache.catalina.startup.Bootstrap "$@" start
  fi

 # +----------------------------------------------------+ # | ......当执行catalina.sh的参数是start的时候...... | # | 在新窗口中启动tomcat服务器！！！ | # +----------------------------------------------------+ 
elif [ "$1" = "start" ] ; then
 # 把参数start去掉 
  shift
 # 创建一个文件（如果文件不存在的话）$CATALINA_BASE/logs/catalina.out 
  touch "$CATALINA_BASE"/logs/catalina.out
 # 如果参数是start -security，则启动Security Manager 
  if [ "$1" = "-security" ] ; then
    echo "Using Security Manager"
    shift
    "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
      -Djava.security.manager \
      -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
      -Dcatalina.base="$CATALINA_BASE" \
      -Dcatalina.home="$CATALINA_HOME" \
      -Djava.io.tmpdir="$CATALINA_TMPDIR" \
      org.apache.catalina.startup.Bootstrap "$@" start \
      >> "$CATALINA_BASE"/logs/catalina.out 2>&1 &

      if [ ! -z "$CATALINA_PID" ]; then
        echo $! > $CATALINA_PID
      fi
      
 # 如果参数是孤单的start，那么在新窗口中启动tomcat 
  else
    "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
      -Djava.endorsed.dirs="$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_BASE"/logs/catalina.out 2>&1 &

      if [ ! -z "$CATALINA_PID" ]; then
        echo $! > $CATALINA_PID
      fi      
  fi

 # +----------------------------------------------------+ # | ......当执行catalina.sh的参数是stop的时候...... | # | 关闭tomcat服务器！！！ | # +----------------------------------------------------+ 
elif [ "$1" = "stop" ] ; then
 # 把参数stop去掉 
  shift
  
 # 关闭tomcat服务器的类是org.apache.catalina.startup.Bootstrap->main("stop"); # 注意：java -D 是设置系统属性   
  exec "$_RUNJAVA" $JAVA_OPTS $CATALINA_OPTS \
    -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
    -Dcatalina.base="$CATALINA_BASE" \
    -Dcatalina.home="$CATALINA_HOME" \
    -Djava.io.tmpdir="$CATALINA_TMPDIR" \
    org.apache.catalina.startup.Bootstrap "$@" stop


 # +----------------------------------------------------+ # | ......当执行catalina.sh的参数不可辨认的时候...... | # | 打印帮助信息，由此查看各种参数代表的意义！！！ | # +----------------------------------------------------+ 
else
  echo "Usage: catalina.sh ( commands ... )"
  echo "commands:"
  echo "  debug             Start Catalina in a debugger"
  echo "  debug -security   Debug Catalina with a security manager"
  echo "  embedded          Start Catalina in embedded mode"
  echo "  jpda start        Start Catalina under JPDA debugger"
  echo "  run               Start Catalina in the current window"
  echo "  run -security     Start in the current window with security manager"
  echo "  start             Start Catalina in a separate window"
  echo "  start -security   Start in a separate window with security manager"
  echo "  stop              Stop Catalina"
  exit 1

fi