Tomcat7启动分析（一）启动脚本

在之前的环境搭建那篇文章里是通过直接运行BootStarp的main函数来启动的，只是加了一个catalina.home的系统属性。而正常情况下启动Tomcat是通过运行脚本的方式，这个就涉及到建立工程时拷贝过来的script目录下的一堆脚本文件了。

以我的windows系统举例，实际上最终是执行startup.bat这个批处理文件来启动tomcat的。

那么启动分析就冲这个文件开始吧：

 

一、分析startup.bat文件 

@echo off
rem Licensed to the Apache Software Foundation (ASF) under one or more
rem contributor license agreements.  See the NOTICE file distributed with
rem this work for additional information regarding copyright ownership.
rem The ASF licenses this file to You under the Apache License, Version 2.0
rem (the "License"); you may not use this file except in compliance with
rem the License.  You may obtain a copy of the License at
rem
rem     http://www.apache.org/licenses/LICENSE-2.0
rem
rem Unless required by applicable law or agreed to in writing, software
rem distributed under the License is distributed on an "AS IS" BASIS,
rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rem See the License for the specific language governing permissions and
rem limitations under the License.

if "%OS%" == "Windows_NT" setlocal
rem ---------------------------------------------------------------------------
rem Start script for the CATALINA Server
rem
rem $Id: startup.bat 895392 2010-01-03 14:02:31Z kkolinko $
rem ---------------------------------------------------------------------------

rem Guess CATALINA_HOME if not defined
set "CURRENT_DIR=%cd%"
if not "%CATALINA_HOME%" == "" goto gotHome
set "CATALINA_HOME=%CURRENT_DIR%"
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
cd ..
set "CATALINA_HOME=%cd%"
cd "%CURRENT_DIR%"
:gotHome
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
echo The CATALINA_HOME environment variable is not defined correctly
echo This environment variable is needed to run this program
goto end
:okHome

set "EXECUTABLE=%CATALINA_HOME%\bin\catalina.bat"

rem Check that target executable exists
if exist "%EXECUTABLE%" goto okExec
echo Cannot find "%EXECUTABLE%"
echo This file is needed to run this program
goto end
:okExec

rem Get remaining unshifted command line arguments and save them in the
set CMD_LINE_ARGS=
:setArgs
if ""%1""=="""" goto doneSetArgs
set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
shift
goto setArgs
:doneSetArgs

call "%EXECUTABLE%" start %CMD_LINE_ARGS%

:end

第1行@echo off的是关闭显示命令行自身的意思，接下来一大堆rem是注释，第17行if "%OS%" == "Windows_NT" setlocal是要临时修改系统变量，方便批处理运行。第26到33行的作用是设置CATALINA_HOME环境变量，如果操作系统中没设置，则将当前运行脚本的目录作为该环境变量的值，最终都会跳转到37行。39到46行验证CATALINA_HOME变量所示目录下的catalina.bat文件是否存在，不存在则批处理直接结束。48到55行将运行脚本前如果设置了其他参数，将参数保存到CMD_LINE_ARGS变量中。最后第57行执行catalina.bat批处理文件，注意，该行后面跟着两个参数，第1个参数是start。

 

二、分析catalina.bat文件 

@echo off
rem Licensed to the Apache Software Foundation (ASF) under one or more
rem contributor license agreements.  See the NOTICE file distributed with
rem this work for additional information regarding copyright ownership.
rem The ASF licenses this file to You under the Apache License, Version 2.0
rem (the "License"); you may not use this file except in compliance with
rem the License.  You may obtain a copy of the License at
rem
rem     http://www.apache.org/licenses/LICENSE-2.0
rem
rem Unless required by applicable law or agreed to in writing, software
rem distributed under the License is distributed on an "AS IS" BASIS,
rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rem See the License for the specific language governing permissions and
rem limitations under the License.

if "%OS%" == "Windows_NT" setlocal
rem ---------------------------------------------------------------------------
rem Start/Stop Script for the CATALINA Server
rem
rem Environment Variable Prerequisites
rem
rem   Do not set the variables in this script. Instead put them into a script
rem   setenv.bat in CATALINA_BASE/bin to keep your customizations separate.
rem
rem   CATALINA_HOME   May point at your Catalina "build" directory.
rem
rem   CATALINA_BASE   (Optional) Base directory for resolving dynamic portions
rem                   of a Catalina installation.  If not present, resolves to
rem                   the same directory that CATALINA_HOME points to.
rem
rem   CATALINA_OPTS   (Optional) Java runtime options used when the "start",
rem                   "run" or "debug" command is executed.
rem                   Include here and not in JAVA_OPTS all options, that should
rem                   only be used by Tomcat itself, not by the stop process,
rem                   the version command etc.
rem                   Examples are heap size, GC logging, JMX ports etc.
rem
rem   CATALINA_TMPDIR (Optional) Directory path location of temporary directory
rem                   the JVM should use (java.io.tmpdir).  Defaults to
rem                   %CATALINA_BASE%\temp.
rem
rem   JAVA_HOME       Must point at your Java Development Kit installation.
rem                   Required to run the with the "debug" argument.
rem
rem   JRE_HOME        Must point at your Java Runtime installation.
rem                   Defaults to JAVA_HOME if empty. If JRE_HOME and JAVA_HOME
rem                   are both set, JRE_HOME is used.
rem
rem   JAVA_OPTS       (Optional) Java runtime options used when any command
rem                   is executed.
rem                   Include here and not in CATALINA_OPTS all options, that
rem                   should be used by Tomcat and also by the stop process,
rem                   the version command etc.
rem                   Most options should go into CATALINA_OPTS.
rem
rem   JAVA_ENDORSED_DIRS (Optional) Lists of of semi-colon separated directories
rem                   containing some jars in order to allow replacement of APIs
rem                   created outside of the JCP (i.e. DOM and SAX from W3C).
rem                   It can also be used to update the XML parser implementation.
rem                   Defaults to $CATALINA_HOME/endorsed.
rem
rem   JPDA_TRANSPORT  (Optional) JPDA transport used when the "jpda start"
rem                   command is executed. The default is "dt_socket".
rem
rem   JPDA_ADDRESS    (Optional) Java runtime options used when the "jpda start"
rem                   command is executed. The default is 8000.
rem
rem   JPDA_SUSPEND    (Optional) Java runtime options used when the "jpda start"
rem                   command is executed. Specifies whether JVM should suspend
rem                   execution immediately after startup. Default is "n".
rem
rem   JPDA_OPTS       (Optional) Java runtime options used when the "jpda start"
rem                   command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS,
rem                   and JPDA_SUSPEND are ignored. Thus, all required jpda
rem                   options MUST be specified. The default is:
rem
rem                   -agentlib:jdwp=transport=%JPDA_TRANSPORT%,
rem                       address=%JPDA_ADDRESS%,server=y,suspend=%JPDA_SUSPEND%
rem
rem   LOGGING_CONFIG  (Optional) Override Tomcat's logging config file
rem                   Example (all one line)
rem                   set LOGGING_CONFIG="-Djava.util.logging.config.file=%CATALINA_BASE%\conf\logging.properties"
rem
rem   LOGGING_MANAGER (Optional) Override Tomcat's logging manager
rem                   Example (all one line)
rem                   set LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
rem
rem   TITLE           (Optional) Specify the title of Tomcat window. The default
rem                   TITLE is Tomcat if it's not specified.
rem                   Example (all one line)
rem                   set TITLE=Tomcat.Cluster#1.Server#1 [%DATE% %TIME%]
rem
rem
rem
rem $Id: catalina.bat 1344732 2012-05-31 14:08:02Z kkolinko $
rem ---------------------------------------------------------------------------

rem Suppress Terminate batch job on CTRL+C
if not ""%1"" == ""run"" goto mainEntry
if "%TEMP%" == "" goto mainEntry
if exist "%TEMP%\%~nx0.run" goto mainEntry
echo Y>"%TEMP%\%~nx0.run"
if not exist "%TEMP%\%~nx0.run" goto mainEntry
echo Y>"%TEMP%\%~nx0.Y"
call "%~f0" %* <"%TEMP%\%~nx0.Y"
rem Use provided errorlevel
set RETVAL=%ERRORLEVEL%
del /Q "%TEMP%\%~nx0.Y" >NUL 2>&1
exit /B %RETVAL%
:mainEntry
del /Q "%TEMP%\%~nx0.run" >NUL 2>&1

rem Guess CATALINA_HOME if not defined
set "CURRENT_DIR=%cd%"
if not "%CATALINA_HOME%" == "" goto gotHome
set "CATALINA_HOME=%CURRENT_DIR%"
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
cd ..
set "CATALINA_HOME=%cd%"
cd "%CURRENT_DIR%"
:gotHome

if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
echo The CATALINA_HOME environment variable is not defined correctly
echo This environment variable is needed to run this program
goto end
:okHome

rem Copy CATALINA_BASE from CATALINA_HOME if not defined
if not "%CATALINA_BASE%" == "" goto gotBase
set "CATALINA_BASE=%CATALINA_HOME%"
:gotBase

rem Ensure that any user defined CLASSPATH variables are not used on startup,
rem but allow them to be specified in setenv.bat, in rare case when it is needed.
set CLASSPATH=

rem Get standard environment variables
if not exist "%CATALINA_BASE%\bin\setenv.bat" goto checkSetenvHome
call "%CATALINA_BASE%\bin\setenv.bat"
goto setenvDone
:checkSetenvHome
if exist "%CATALINA_HOME%\bin\setenv.bat" call "%CATALINA_HOME%\bin\setenv.bat"
:setenvDone

rem Get standard Java environment variables
if exist "%CATALINA_HOME%\bin\setclasspath.bat" goto okSetclasspath
echo Cannot find "%CATALINA_HOME%\bin\setclasspath.bat"
echo This file is needed to run this program
goto end
:okSetclasspath
call "%CATALINA_HOME%\bin\setclasspath.bat" %1
if errorlevel 1 goto end

rem Add on extra jar file to CLASSPATH
rem Note that there are no quotes as we do not want to introduce random
rem quotes into the CLASSPATH
if "%CLASSPATH%" == "" goto emptyClasspath
set "CLASSPATH=%CLASSPATH%;"
:emptyClasspath
set "CLASSPATH=%CLASSPATH%%CATALINA_HOME%\bin\bootstrap.jar"

if not "%CATALINA_TMPDIR%" == "" goto gotTmpdir
set "CATALINA_TMPDIR=%CATALINA_BASE%\temp"
:gotTmpdir

rem Add tomcat-juli.jar to classpath
rem tomcat-juli.jar can be over-ridden per instance
if not exist "%CATALINA_BASE%\bin\tomcat-juli.jar" goto juliClasspathHome
set "CLASSPATH=%CLASSPATH%;%CATALINA_BASE%\bin\tomcat-juli.jar"
goto juliClasspathDone
:juliClasspathHome
set "CLASSPATH=%CLASSPATH%;%CATALINA_HOME%\bin\tomcat-juli.jar"
:juliClasspathDone

if not "%LOGGING_CONFIG%" == "" goto noJuliConfig
set LOGGING_CONFIG=-Dnop
if not exist "%CATALINA_BASE%\conf\logging.properties" goto noJuliConfig
set LOGGING_CONFIG=-Djava.util.logging.config.file="%CATALINA_BASE%\conf\logging.properties"
:noJuliConfig
set JAVA_OPTS=%JAVA_OPTS% %LOGGING_CONFIG%

if not "%LOGGING_MANAGER%" == "" goto noJuliManager
set LOGGING_MANAGER=-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
:noJuliManager
set JAVA_OPTS=%JAVA_OPTS% %LOGGING_MANAGER%

rem ----- Execute The Requested Command ---------------------------------------

echo Using CATALINA_BASE:   "%CATALINA_BASE%"
echo Using CATALINA_HOME:   "%CATALINA_HOME%"
echo Using CATALINA_TMPDIR: "%CATALINA_TMPDIR%"
if ""%1"" == ""debug"" goto use_jdk
echo Using JRE_HOME:        "%JRE_HOME%"
goto java_dir_displayed
:use_jdk
echo Using JAVA_HOME:       "%JAVA_HOME%"
:java_dir_displayed
echo Using CLASSPATH:       "%CLASSPATH%"

set _EXECJAVA=%_RUNJAVA%
set MAINCLASS=org.apache.catalina.startup.Bootstrap
set ACTION=start
set SECURITY_POLICY_FILE=
set DEBUG_OPTS=
set JPDA=

if not ""%1"" == ""jpda"" goto noJpda
set JPDA=jpda
if not "%JPDA_TRANSPORT%" == "" goto gotJpdaTransport
set JPDA_TRANSPORT=dt_socket
:gotJpdaTransport
if not "%JPDA_ADDRESS%" == "" goto gotJpdaAddress
set JPDA_ADDRESS=8000
:gotJpdaAddress
if not "%JPDA_SUSPEND%" == "" goto gotJpdaSuspend
set JPDA_SUSPEND=n
:gotJpdaSuspend
if not "%JPDA_OPTS%" == "" goto gotJpdaOpts
set JPDA_OPTS=-agentlib:jdwp=transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=%JPDA_SUSPEND%
:gotJpdaOpts
shift
:noJpda

if ""%1"" == ""debug"" goto doDebug
if ""%1"" == ""run"" goto doRun
if ""%1"" == ""start"" goto doStart
if ""%1"" == ""stop"" goto doStop
if ""%1"" == ""configtest"" goto doConfigTest
if ""%1"" == ""version"" goto doVersion

echo Usage:  catalina ( commands ... )
echo commands:
echo   debug             Start Catalina in a debugger
echo   debug -security   Debug Catalina with a security manager
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   configtest        Run a basic syntax check on server.xml
echo   version           What version of tomcat are you running?
goto end

:doDebug
shift
set _EXECJAVA=%_RUNJDB%
set DEBUG_OPTS=-sourcepath "%CATALINA_HOME%\..\..\java"
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd

:doRun
shift
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd

:doStart
shift
if not "%OS%" == "Windows_NT" goto noTitle
if "%TITLE%" == "" set TITLE=Tomcat
set _EXECJAVA=start "%TITLE%" %_RUNJAVA%
goto gotTitle
:noTitle
set _EXECJAVA=start %_RUNJAVA%
:gotTitle
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd

:doStop
shift
set ACTION=stop
set CATALINA_OPTS=
goto execCmd

:doConfigTest
shift
set ACTION=configtest
set CATALINA_OPTS=
goto execCmd

:doVersion
%_EXECJAVA% -classpath "%CATALINA_HOME%\lib\catalina.jar" org.apache.catalina.util.ServerInfo
goto end


:execCmd
rem Get remaining unshifted command line arguments and save them in the
set CMD_LINE_ARGS=
:setArgs
if ""%1""=="""" goto doneSetArgs
set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
shift
goto setArgs
:doneSetArgs

rem Execute Java with the applicable properties
if not "%JPDA%" == "" goto doJpda
if not "%SECURITY_POLICY_FILE%" == "" goto doSecurity
%_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doSecurity
%_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doJpda
if not "%SECURITY_POLICY_FILE%" == "" goto doSecurityJpda
%_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %JPDA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doSecurityJpda
%_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %JPDA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end

:end

1到99行一大堆注释说明就不看了，100到110行一堆run文件校验之类的一般用不到，直接跳到111行，接下来先删除上面可能产生的中间文件，接着按照正常流程，在上面的startup.bat文件中已经设置过CATALINA_HOME变量，并且校验了改变量下bin\catalina.bat文件已经存在（我猜作者写这一段是防止用户直接运行catalina.bat文件）。经过这些判断后跳转到128行，130到133行设置CATALINA_BASE变量，中间几行注释略过，139到144行如果有setenv.bat文件则执行一下该文件。147到153行执行setclasspath.bat文件（该文件在同级目录下已经提供，具体脚本下面已经贴出来了，可以读一下，这里不再做分析。主要功能校验是否设置JAVA_HOME变量，没有则在控制台显示出提示信息。注意该文件中第79行将会设置_RUNJAVA变量，该变量的值即JAVA_HOME或JRE_HOME的bin目录下的java.exe文件）。从156到224行校验并设置一堆变量（注意第202、203和204行，最后启动分析时将会用到）。226到231行将根据调用catalina.bat时设置的参数决定跳转，按照上一段的最后的说明，此时将会跳转到doStart标记行。从265行开始，校验和设置一些变量之后（注意第269行）将会跳转到execCmd标记行，即297行。297到305行作用是将系统参数保存到CMD_LINE_ARGS变量中。

 

接下来便是谜底解开的时候，正常情况下将会执行到310行，这里单独贴出来分析一下：

%_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%

 

按照202行的提示_EXECJAVA一开始的值等于_RUNJAVA，但在269行将该值改成了start "%TITLE%" %_RUNJAVA%，这里的作用是另启动一个命令行窗口，并给窗口起名，最终还是执行java.exe文件。从%JAVA_OPTS%开始到%MAINCLASS%之前都是在设置运行时参数和系统属性，%MAINCLASS%即203行的org.apache.catalina.startup.Bootstrap，后面是其它的命令行参数，最后一个参数%ACTION%在204行时被设置成start。归结起来一句话，即执行Bootstrap类的main方法。

 

setclasspath.bat:

@echo off
rem Licensed to the Apache Software Foundation (ASF) under one or more
rem contributor license agreements.  See the NOTICE file distributed with
rem this work for additional information regarding copyright ownership.
rem The ASF licenses this file to You under the Apache License, Version 2.0
rem (the "License"); you may not use this file except in compliance with
rem the License.  You may obtain a copy of the License at
rem
rem     http://www.apache.org/licenses/LICENSE-2.0
rem
rem Unless required by applicable law or agreed to in writing, software
rem distributed under the License is distributed on an "AS IS" BASIS,
rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rem See the License for the specific language governing permissions and
rem limitations under the License.

rem ---------------------------------------------------------------------------
rem Set JAVA_HOME or JRE_HOME if not already set, ensure any provided settings
rem are valid and consistent with the selected start-up options and set up the
rem endorsed directory.
rem
rem $Id: setclasspath.bat 1202062 2011-11-15 06:50:02Z mturk $
rem ---------------------------------------------------------------------------

rem Make sure prerequisite environment variables are set

rem In debug mode we need a real JDK (JAVA_HOME)
if ""%1"" == ""debug"" goto needJavaHome

rem Otherwise either JRE or JDK are fine
if not "%JRE_HOME%" == "" goto gotJreHome
if not "%JAVA_HOME%" == "" goto gotJavaHome
echo Neither the JAVA_HOME nor the JRE_HOME environment variable is defined
echo At least one of these environment variable is needed to run this program
goto exit

:needJavaHome
rem Check if we have a usable JDK
if "%JAVA_HOME%" == "" goto noJavaHome
if not exist "%JAVA_HOME%\bin\java.exe" goto noJavaHome
if not exist "%JAVA_HOME%\bin\javaw.exe" goto noJavaHome
if not exist "%JAVA_HOME%\bin\jdb.exe" goto noJavaHome
if not exist "%JAVA_HOME%\bin\javac.exe" goto noJavaHome
set "JRE_HOME=%JAVA_HOME%"
goto okJava

:noJavaHome
echo The JAVA_HOME environment variable is not defined correctly.
echo It is needed to run this program in debug mode.
echo NB: JAVA_HOME should point to a JDK not a JRE.
goto exit

:gotJavaHome
rem No JRE given, use JAVA_HOME as JRE_HOME
set "JRE_HOME=%JAVA_HOME%"

:gotJreHome
rem Check if we have a usable JRE
if not exist "%JRE_HOME%\bin\java.exe" goto noJreHome
if not exist "%JRE_HOME%\bin\javaw.exe" goto noJreHome
goto okJava

:noJreHome
rem Needed at least a JRE
echo The JRE_HOME environment variable is not defined correctly
echo This environment variable is needed to run this program
goto exit

:okJava
rem Don't override the endorsed dir if the user has set it previously
if not "%JAVA_ENDORSED_DIRS%" == "" goto gotEndorseddir
rem Set the default -Djava.endorsed.dirs argument
set "JAVA_ENDORSED_DIRS=%CATALINA_HOME%\endorsed"
:gotEndorseddir

rem Set standard command for invoking Java.
rem Note that NT requires a window name argument when using start.
rem Also note the quoting as JAVA_HOME may contain spaces.
set _RUNJAVA="%JRE_HOME%\bin\java"
set _RUNJDB="%JAVA_HOME%\bin\jdb"

goto end

:exit
exit /b 1

:end
exit /b 0

 

三、总结

以上即tomcat的启动脚本中的总体流程，只是讲了默认的脚本运行方式，但在脚本阅读中可以看到能根据catalina.bat里可以根据不同参数以不同方式运行tomcat：

debug             Start Catalina in a debugger

debug -security   Debug Catalina with a security manager

jpda start        Start Catalina under JPDA debugger

run               Start Catalina in the current window

run -security     Start in the current window with security manager

start             Start Catalina in a separate window

start -security   Start in a separate window with security manager

stop              Stop Catalina

configtest        Run a basic syntax check on server.xml

 

只要能看懂基本dos命令，这几个脚本的阅读其实很简单，其他bat文件可以大体浏览一下，会发现转了半天，最终都会执行catalina.bat文件，而catalina.bat文件里最终会执行Bootstrap文件的main方法，不同的是调用main方法时会各自添加不同的入参而已。bat文件用于windows操作系统下启动tomcat，而sh文件则用于unix环境下的启动，原理是一致的。