分析catalina.sh脚本的目的，一个是学习脚本中shell的各类用法，还有就是为编写tomcat多服务器远程启动脚本做准备，实现版本上线自动化无人干预部署，此前作者已发表“ tomcat变量环境脚本setclasspath.sh分析”来为此篇作为铺垫，需要两篇文章一起看，才能全面的分析出tomcat的启动过程。
tomcat版本：6.0.35
#!/bin/sh # Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ----------------------------------------------------------------------------- # Start/Stop Script for the CATALINA Server # # Environment Variable Prerequisites # # 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_OUT (Optional) Full path to a file where stdout and stderr # will be redirected. # Default is $CATALINA_BASE/logs/catalina.out # # CATALINA_OPTS (Optional) Java runtime options used when the "start", # 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. # Required to run the with the "debug" argument. # # JRE_HOME Must point at your Java Development Kit installation. # Defaults to JAVA_HOME if empty. # # JAVA_OPTS (Optional) Java runtime options used when the "start", # "stop", or "run" command is executed. # # JAVA_ENDORSED_DIRS (Optional) Lists of of colon separated directories # containing some jars in order to allow replacement of APIs # created outside of the JCP (i.e. DOM and SAX from W3C). # It can also be used to update the XML parser implementation. # Defaults to $CATALINA_HOME/endorsed. # # JPDA_TRANSPORT (Optional) JPDA transport used when the "jpda start" # command is executed. The default is "dt_socket". # # JPDA_ADDRESS (Optional) Java runtime options used when the "jpda start" # command is executed. The default is 8000. # # JPDA_SUSPEND (Optional) Java runtime options used when the "jpda start" # command is executed. Specifies whether JVM should suspend # execution immediately after startup. Default is "n". # # JPDA_OPTS (Optional) Java runtime options used when the "jpda start" # command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS, # and JPDA_SUSPEND are ignored. Thus, all required jpda # options MUST be specified. The default is: # # -agentlib:jdwp=transport=$JPDA_TRANSPORT, # address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND # # CATALINA_PID (Optional) Path of the file which should contains the pid # of catalina startup java process, when start (fork) is used # # LOGGING_CONFIG (Optional) Override Tomcat‘s logging config file # Example (all one line) # LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties" # # LOGGING_MANAGER (Optional) Override Tomcat‘s logging manager # Example (all one line) # LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager" # # $Id: catalina.sh 1146097 2011-07-13 15:25:05Z markt $ # ----------------------------------------------------------------------------- export JRE_HOME=/usr/java/jdk1.6.0_38 export CATALINA_HOME=/home/xrltest1/tomcat JAVA_OPTS="-server -Xms2048m -Xmx2048m -Xmn768m -XX:PermSize=128m -XX:MaxPermSize=256m -XX:+UseParallelOldGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/xrltest1/tomcat/dumpfile/heap.bin -Xloggc:/home/xrltest1/tomcat/logs/gc.log" #作者添加的环境申明，如果一台服务器中有多台tomcat要使用不同版本的JVM，就可以直接这这边添加JRE_HOME，不需要再/etc/profile.d中再配置JRE_HOME环境变量 # OS specific support. $var _must_ be set to either true or false. #此处语句判断操作系统，同时对操作系统支持 #os400是 IBM的AIX #darwin是MacOSX 操作环境的操作系统成份 #Darwin是windows平台上运行的类UNIX模拟环境 cygwin=false os400=false darwin=false case "`uname`" in CYGWIN*) cygwin=true;; OS400*) os400=true;; Darwin*) darwin=true;; esac # resolve links - $0 may be a softlink #此处的RPG抓取的是文件名，因为可能是符号链接，所以下面循环语句的作用就是找到文件真实源路径 PRG="$0" while [ -h "$PRG" ]; do ls=`ls -ld "$PRG"` link=`expr "$ls" : ‘.*-> \(.*\)$‘` if expr "$link" : ‘/.*‘ > /dev/null; then PRG="$link" else PRG=`dirname "$PRG"`/"$link" fi done #获取脚本目录真实目录地址 # Get standard environment variables PRGDIR=`dirname "$PRG"` # Only set CATALINA_HOME if not already set [ -z "$CATALINA_HOME" ] && CATALINA_HOME=`cd "$PRGDIR/.." >/dev/null; pwd` # Copy CATALINA_BASE from CATALINA_HOME if not already set [ -z "$CATALINA_BASE" ] && CATALINA_BASE="$CATALINA_HOME" #上面两个语句判断变量$CATALINA_HOME和$CATALINA_BASE是否存在，不存在则给予附值 #CATALINA_BASE="$CATALINA_HOME" # Ensure that any user defined CLASSPATH variables are not used on startup, # but allow them to be specified in setenv.sh, in rare case when it is needed. CLASSPATH= #test –r File 文件存在并且可读 if [ -r "$CATALINA_BASE/bin/setenv.sh" ]; then . "$CATALINA_BASE/bin/setenv.sh" elif [ -r "$CATALINA_HOME/bin/setenv.sh" ]; then . "$CATALINA_HOME/bin/setenv.sh" fi #默认的tomcat的bin目录下没有这个文件，可以自行编写setenv.sh这个文件设定环境变量 # For Cygwin, ensure paths are in UNIX format before anything is touched if $cygwin; then [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"` [ -n "$JRE_HOME" ] && JRE_HOME=`cygpath --unix "$JRE_HOME"` [ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"` [ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"` [ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"` fi # For OS400 if $os400; then # Set job priority to standard for interactive (interactive - 6) by using # the interactive priority - 6, the helper threads that respond to requests # will be running at the same priority as interactive jobs. COMMAND=‘chgjob job(‘$JOBNAME‘) runpty(6)‘ system $COMMAND # Enable multi threading export QIBM_MULTI_THREADED=Y fi # Get standard Java environment variables if $os400; then # -r will Only work on the os400 if the files are: # 1. owned by the user # 2. owned by the PRIMARY group of the user # this will not work if the user belongs in secondary groups BASEDIR="$CATALINA_HOME" . "$CATALINA_HOME"/bin/setclasspath.sh else #这点一定要注意了，本脚本中没有赋值却突然冒出的变量 #都是在setclasspath.sh这个脚本中执行赋值的。比如$_RUNJAVA #作者会在下一篇文章中，分析setclasspath.sh这个脚本 if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then BASEDIR="$CATALINA_HOME" . "$CATALINA_HOME"/bin/setclasspath.sh else echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh" echo "This file is needed to run this program" exit 1 fi fi #以上是出现在其他操作环境下的脚本的可用性设置，因默认linux系统，上面就不做解读了 if [ -z "$CATALINA_BASE" ] ; then CATALINA_BASE="$CATALINA_HOME" fi #将变量赋值 # Add tomcat-juli.jar and bootstrap.jar to classpath # tomcat-juli.jar can be over-ridden per instance if [ ! -z "$CLASSPATH" ] ; then CLASSPATH="$CLASSPATH": fi #虽然前面已将做出CATALINA_BASE="$CATALINA_HOME"的语句 #此处还是添加了判断，增强了代码的健壮性 #添加变量$CLASSPATH的值 if [ "$CATALINA_BASE" != "$CATALINA_HOME" ] && [ -r "$CATALINA_BASE/bin/tomcat-juli.jar" ] ; then CLASSPATH="$CLASSPATH""$CATALINA_BASE"/bin/tomcat-juli.jar:"$CATALINA_HOME"/bin/bootstrap.jar else CLASSPATH="$CLASSPATH""$CATALINA_HOME"/bin/bootstrap.jar fi #确认日志路径$CATALINA_OUT #这部分主要判断这些变量是否预定义，有就以预定义为主，没有就设置为默认格式 if [ -z "$CATALINA_OUT" ] ; then CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out fi if [ -z "$CATALINA_TMPDIR" ] ; then # Define the java.io.tmpdir to use for Catalina CATALINA_TMPDIR="$CATALINA_BASE"/temp fi # Bugzilla 37848: When no TTY is available, don‘t output to console #获取当前shell运行的终端设备 have_tty=0 if [ "`tty`" != "not a tty" ]; then have_tty=1 fi # For Cygwin, switch paths to Windows format before running java if $cygwin; then JAVA_HOME=`cygpath --absolute --windows "$JAVA_HOME"` JRE_HOME=`cygpath --absolute --windows "$JRE_HOME"` CATALINA_HOME=`cygpath --absolute --windows "$CATALINA_HOME"` CATALINA_BASE=`cygpath --absolute --windows "$CATALINA_BASE"` CATALINA_TMPDIR=`cygpath --absolute --windows "$CATALINA_TMPDIR"` CLASSPATH=`cygpath --path --windows "$CLASSPATH"` JAVA_ENDORSED_DIRS=`cygpath --path --windows "$JAVA_ENDORSED_DIRS"` fi # Set juli LogManager config file if it is present and an override has not been issued #确认$LOGGING_CONFIG变量 if [ -z "$LOGGING_CONFIG" ]; then if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties" else # Bugzilla 45585 LOGGING_CONFIG="-Dnop" fi fi #确认$LOGGING_MANAGER变量 if [ -z "$LOGGING_MANAGER" ]; then JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager" else JAVA_OPTS="$JAVA_OPTS $LOGGING_MANAGER" fi # ----- Execute The Requested Command ----------------------------------------- # Bugzilla 37848: only output this if we have a TTY #正常情况下have_tty=1 if [ $have_tty -eq 1 ]; then echo "Using CATALINA_BASE: $CATALINA_BASE" echo "Using CATALINA_HOME: $CATALINA_HOME" echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR" if [ "$1" = "debug" ] ; then echo "Using JAVA_HOME: $JAVA_HOME" else echo "Using JRE_HOME: $JRE_HOME" fi echo "Using CLASSPATH: $CLASSPATH" #以下这句判断设置的$CATALINA_PID变量如果不存在，则显示"Using CATALINA_PID: $CATALINA_PID"，如果存在则不显示 if [ ! -z "$CATALINA_PID" ]; then echo "Using CATALINA_PID: $CATALINA_PID" fi fi #以上就是在启动tomcat是输出的环境变量信息 # #获取第一次参数，jpda在后面的说明为：jpda start Start Catalina under JPDA debugger 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_SUSPEND" ]; then JPDA_SUSPEND="n" fi if [ -z "$JPDA_OPTS" ]; then JPDA_OPTS="-agentlib:jdwp=transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND" fi CATALINA_OPTS="$CATALINA_OPTS $JPDA_OPTS" shift fi #JPDA 模式是开启远程debug模式，端口就是JPDA_ADDRESS,生产环境用不到，不去深入 #这个是debug模式 #值得注意的是变量$_RUNJDB，居然在全文没有找到赋值的语句。 #从这边开始就注意了，里面的if-fi判断很多，一定要先调好格式再看 if [ "$1" = "debug" ] ; then if $os400; then echo "Debug command not available on OS400" exit 1 else shift if [ "$1" = "-security" ] ; then if [ $have_tty -eq 1 ]; then echo "Using Security Manager" fi shift exec "$_RUNJDB" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" -sourcepath "$CATALINA_HOME"/../../java -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" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" -sourcepath "$CATALINA_HOME"/../../java -Dcatalina.base="$CATALINA_BASE" -Dcatalina.home="$CATALINA_HOME" -Djava.io.tmpdir="$CATALINA_TMPDIR" org.apache.catalina.startup.Bootstrap "$@" start fi fi #上面语句是适配AIX环境的，不做解读 #当参数是debug时 elif [ "$1" = "run" ]; then shift #当使用shift命令之后，原来的$2会变成$1，并且原有的$1变得不可用，通过$#命令获得的参数个数也会少1 #这样就可以使用$1获取第二个参数 if [ "$1" = "-security" ] ; then if [ $have_tty -eq 1 ]; then echo "Using Security Manager" fi shift #作废掉前两个参数 exec "$_RUNJAVA" "$LOGGING_CONFIG" $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 else exec "$_RUNJAVA" "$LOGGING_CONFIG" $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 "$@" start #这个命令其实就是java命令，指定org.apache.catalina.startup.Bootstrap 这个class文件，$@和"start"作用类似于传参到前面的安格class里 fi #正式进入启动的过程啦~ elif [ "$1" = "start" ] ; then if [ ! -z "$CATALINA_PID" ]; then #test –z 字符串 字符串的长度为零 ,判断这个变量或者文件内有数据 if [ -f "$CATALINA_PID" ]; then #-f 该『文件名』是否为文件(file)？(常用) if [ -s "$CATALINA_PID" ]; then #-s 侦测该文件名是否为『非空白文件』？ echo "Existing PID file found during start." if [ -r "$CATALINA_PID" ]; then #-r 侦测该文件名是否具有『可读』的属性？ #以上if语句主要判断这个$CATALINA_PID，是否能正常可读 PID=`cat "$CATALINA_PID"` ps -p $PID >/dev/null 2>&1 if [ $? -eq 0 ] ; then #判断这个ＰＩＤ现在有没有被占用，有就输出这个tomcat依旧在运行，退出 #上面这段语句功能非常好，可以判断出这个PID是否还在运行 echo "Tomcat appears to still be running with PID $PID. Start aborted." exit 1 else echo "Removing/clearing stale PID file." rm -f "$CATALINA_PID" >/dev/null 2>&1 #删除了这个$CATALINA_PID文件 if [ $? != 0 ]; then if [ -w "$CATALINA_PID" ]; then #-w 侦测该文件名是否具有『可写』的属性？ cat /dev/null > "$CATALINA_PID" #清空$CATALINA_PID文件 else #如果不具有可写权限，则输出信息，退出 echo "Unable to remove or clear stale PID file. Start aborted." exit 1 fi fi fi else #如果"$CATALINA_PID"没有可读权限，任然输出信息退出。 echo "Unable to read PID file. Start aborted." exit 1 fi else #"$CATALINA_PID"是空白文件 rm -f "$CATALINA_PID" >/dev/null 2>&1 #强制删除$CATALINA_PID文件 if [ $? != 0 ]; then #成功则进行判断，没有读权限则退出脚本 if [ ! -w "$CATALINA_PID" ]; then echo "Unable to remove or write to empty PID file. Start aborted." exit 1 fi fi fi fi fi #这段语句，主要目的就是清空$CATALINA_PID文件，如果出现不可读写，则输出信息退出 shift #作废掉前面参数，$1将表示第二个参数 touch "$CATALINA_OUT" #创建$CATALINA_OUT变量路径文件 if [ "$1" = "-security" ] ; then #如果第二个参数是-security if [ $have_tty -eq 1 ]; then echo "Using Security Manager" fi shift "$_RUNJAVA" "$LOGGING_CONFIG" $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 >> "$CATALINA_OUT" 2>&1 & else #我们平时执行启动tomcat核心就是这一句了 # "$_RUNJAVA" "$LOGGING_CONFIG" $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_OUT" 2>&1 & #从&可以看出启动的命令在后台启动 fi if [ ! -z "$CATALINA_PID" ]; then #判断CATALINA_PID如果不是空字符，则将Shell最后运行的后台Process的PID 传给$CATALINA_PID echo $! > "$CATALINA_PID" #在使用命令运行进程至后台时，可以使用$!抓取前面启动运行在后台进程的进程号 fi fi #下面开始了tomcat停止模块了 elif [ "$1" = "stop" ] ; then shift SLEEP=5 if [ ! -z "$1" ]; then echo $1 | grep "[^0-9]" >/dev/null 2>&1 if [ $? -gt 0 ]; then SLEEP=$1 shift fi fi #上面语句主要是判断停止语句执行到此时，设定几秒后再执行停止语句 #用来配合stop n FORCE=0 if [ "$1" = "-force" ]; then shift FORCE=1 fi #如果参数中使用了-force，则FORCE=1 if [ ! -z "$CATALINA_PID" ]; then #$CATALINA_PID文件不是非空 if [ -f "$CATALINA_PID" ]; then if [ -s "$CATALINA_PID" ]; then kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1 #kill -0 pid 不发送任何信号，但是系统会进行错误检查。 if [ $? -gt 0 ]; then echo "PID file found but no matching process was found. Stop aborted." exit 1 fi else echo "PID file is empty and has been ignored." fi else echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted." exit 1 fi fi #以上脚本是进行停止命令检错的，如果可能停止不了，则可以直接报错 "$_RUNJAVA" $JAVA_OPTS -Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" -Dcatalina.base="$CATALINA_BASE" -Dcatalina.home="$CATALINA_HOME" -Djava.io.tmpdir="$CATALINA_TMPDIR" org.apache.catalina.startup.Bootstrap "$@" stop #这个就是停止脚本的核心命令了 if [ ! -z "$CATALINA_PID" ]; then if [ -f "$CATALINA_PID" ]; then while [ $SLEEP -ge 0 ]; do kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1 if [ $? -gt 0 ]; then rm -f "$CATALINA_PID" >/dev/null 2>&1 if [ $? != 0 ]; then if [ -w "$CATALINA_PID" ]; then cat /dev/null > "$CATALINA_PID" else echo "Tomcat stopped but the PID file could not be removed or cleared." fi fi break fi if [ $SLEEP -gt 0 ]; then sleep 1 fi if [ $SLEEP -eq 0 ]; then if [ $FORCE -eq 0 ]; then echo "Tomcat did not stop in time. PID file was not removed." fi fi SLEEP=`expr $SLEEP - 1 ` done fi fi #上段语句主要是清空$CATALINA_PID #值得注意的是，生产环境偶尔不加-force选项，tomcat有时无法停止下来 #如果参数带"-force" ，则强制kill掉tomcat if [ $FORCE -eq 1 ]; then if [ -z "$CATALINA_PID" ]; then echo "Kill failed: \$CATALINA_PID not set" else if [ -f "$CATALINA_PID" ]; then PID=`cat "$CATALINA_PID"` echo "Killing Tomcat with the PID: $PID" kill -9 $PID #强制执行的核心命令 rm -f "$CATALINA_PID" >/dev/null 2>&1 if [ $? != 0 ]; then echo "Tomcat was killed but the PID file could not be removed." fi fi fi fi #查看版本参数 elif [ "$1" = "version" ] ; then "$_RUNJAVA" -classpath "$CATALINA_HOME/lib/catalina.jar" org.apache.catalina.util.ServerInfo else echo "Usage: catalina.sh ( commands ... )" echo "commands:" if $os400; then echo " debug Start Catalina in a debugger (not available on OS400)" echo " debug -security Debug Catalina with a security manager (not available on OS400)" else echo " debug Start Catalina in a debugger" echo " debug -security Debug Catalina with a security manager" fi 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, waiting up to 5 seconds for the process to end" echo " stop n Stop Catalina, waiting up to n seconds for the process to end" echo " stop -force Stop Catalina, wait up to 5 seconds and then use kill -KILL if still running" echo " stop n -force Stop Catalina, wait up to n seconds and then use kill -KILL if still running" echo " version What version of tomcat are you running?" echo "Note: Waiting for the process to end and use of the -force option require that \$CATALINA_PID is defined" exit 1 fi
总结下，catalina.sh脚本使用了大量的判断，使用if作为参数的输入判断，核心的启动命令其实就是java命令。如果在发生tomcat启动异常，大家就可以排查时在catalina.sh完成时出现问题，还是catalina.sh启动后出现异常，如果有想要更加深入的小伙伴，可以学习下java，会在JVM调优和排障上会走的更远。
本文出自 “运维路上” 博客，请务必保留此出处http://vekergu.blog.51cto.com/9966832/1622442
原文地址：http://vekergu.blog.51cto.com/9966832/1622442
