catalina.sh详解

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