tomcat启动分析（2）
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"
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 classif [ -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=$CATALINA_HOMEif [ -z "$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/tempif [ -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