深入刨析tomcat 之---第12篇 how tomcat works( 第17章 ) 解析catalina.bat 梳理启动流程

我们如何启动tomcat呢? 答案是双击startup.bat文件,这个文件在bin目录下

 

@echo off    不显示批处理命令

rem Licensed to the Apache Software Foundation (ASF) under one or more
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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
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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 743401 2009-02-11 17:01:58Z markt $
rem ---------------------------------------------------------------------------

rem Guess CATALINA_HOME if not defined
if not "%CATALINA_HOME%" == "" goto gotHome
set CATALINA_HOME=.
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
set CATALINA_HOME=..
: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       //如果第一个参数为" ",就是 在命令行敲入startup 命令;如果让%1不得"""" ,那么就这样输入 startup start
set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1   如果有参数CMD_LINE_ARGS 变量的值为 参数1的值
shift
goto setArgs
:doneSetArgs

call "%EXECUTABLE%" start %CMD_LINE_ARGS%  最终的命令为  bin\catalina.bat  start  

:end

以上批处理文件执行完成就变为了一句话,就是 在cmd 窗口中打   bin\catalina.bat  start  

那么接着执行catalina 批处理

 

set CATALINA_OPTS=%CATALINA_OPTS% -Dsun.io.useCanonCaches=false

rem Guess CATALINA_HOME if not defined
if not "%CATALINA_HOME%" == "" goto gotHome
set CATALINA_HOME=.
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
set CATALINA_HOME=..
: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 Get standard environment variables
if exist "%CATALINA_HOME%\bin\setenv.bat" call "%CATALINA_HOME%\bin\setenv.bat"

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
set BASEDIR=%CATALINA_HOME%
call "%CATALINA_HOME%\bin\setclasspath.bat"

rem Add on extra jar files to CLASSPATH
if "%JSSE_HOME%" == "" goto noJsse
set CLASSPATH=%CLASSPATH%;%JSSE_HOME%\lib\jcert.jar;%JSSE_HOME%\lib\jnet.jar;%JSSE_HOME%\lib\jsse.jar
:noJsse
set CLASSPATH=%CLASSPATH%;%CATALINA_HOME%\bin\bootstrap.jar

if not "%CATALINA_BASE%" == "" goto gotBase
set CATALINA_BASE=%CATALINA_HOME%
:gotBase

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

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

echo Using CATALINA_BASE: %CATALINA_BASE%
echo Using CATALINA_HOME: %CATALINA_HOME%
echo Using CATALINA_TMPDIR: %CATALINA_TMPDIR%
echo Using JAVA_HOME: %JAVA_HOME%

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

if not ""%1"" == ""jpda"" goto noJpda
set JPDA=jpda
if not "%JPDA_TRANSPORT%" == "" goto gotJpdaTransport
set JPDA_TRANSPORT=dt_shmem
:gotJpdaTransport
if not "%JPDA_ADDRESS%" == "" goto gotJpdaAddress
set JPDA_ADDRESS=jdbconn
:gotJpdaAddress
shift
:noJpda
echo print 参数1 ""%1""
if ""%1"" == ""debug"" goto doDebug
if ""%1"" == ""embedded"" goto doEmbedded
if ""%1"" == ""run"" goto doRun
if ""%1"" == ""start"" goto doStart
if ""%1"" == ""stop"" goto doStop

echo Usage: catalina ( 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
goto end

:doDebug
shift
set _EXECJAVA=%_RUNJDB%
set DEBUG_OPTS=-sourcepath "%CATALINA_HOME%\..\..\jakarta-tomcat-4.0\catalina\src\share"
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy
goto execCmd

:doEmbedded
shift
set MAINCLASS=org.apache.catalina.startup.Embedded
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
set _EXECJAVA=start "Tomcat" %_RUNJAVA%
echo Print _EXECJAVA %_EXECJAVA%
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
goto execCmd

: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%
echo lastword %_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% -Xdebug -Xrunjdwp:transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=n %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% -Xrunjdwp:transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=n %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

 

最后打印的内容为

D:\dev\apache-tomcat-4.1.40\bin>catalina.bat start
Using CATALINA_BASE: ..
Using CATALINA_HOME: ..
Using CATALINA_TMPDIR: ..\temp
Using JAVA_HOME: D:\dev\JDK8
Using _EXECJAVA "D:\dev\JDK8\bin\java"
print 鍙傛暟1 ""start""
Print _EXECJAVA start "Tomcat" "D:\dev\JDK8\bin\java"
最终指令::==>  start "Tomcat" "D:\dev\JDK8\bin\java" -Dsun.io.useCanonCaches=false -Djava.endorsed.dirs="..\common\endorsed" -classpath "D:\dev\JDK8\lib\tools.jar;..\bin\bootstrap.jar" -Dcatalina.base=".." -Dcatalina.home=".." -Djava.io.tmpdir="..\temp" org.apache.catalina.startup.Bootstrap start

 

start "Tomcat" 是启动一个新cmd 窗口命名为"Tomcat",那么最后的只看指令就是java  -classpath   ..\bin\bootstrap.jar"  org.apache.catalina.startup.Bootstrap start

那么类路径在bin下面有一个 bootstrap.jar文件,如果你打开看就是

org.apache.catalina.startup.Bootstrap类

    public static void main(String args[]) {

        // Set the debug flag appropriately
        for (int i = 0; i < args.length; i++)  {
            if ("-debug".equals(args[i]))
                debug = 1;
        }
        
        // Configure catalina.base from catalina.home if not yet set
        if (System.getProperty("catalina.base") == null)
            System.setProperty("catalina.base", getCatalinaHome());

        // Construct the class loaders we will need
        ClassLoader commonLoader = null;
        ClassLoader catalinaLoader = null;
        ClassLoader sharedLoader = null;
        try {

            File unpacked[] = new File[1];
            File packed[] = new File[1];
            File packed2[] = new File[2];
            ClassLoaderFactory.setDebug(debug);

            unpacked[0] = new File(getCatalinaHome(),
                                   "common" + File.separator + "classes");
            packed2[0] = new File(getCatalinaHome(),
                                  "common" + File.separator + "endorsed");
            packed2[1] = new File(getCatalinaHome(),
                                  "common" + File.separator + "lib");
            commonLoader =
                ClassLoaderFactory.createClassLoader(unpacked, packed2, null);

            unpacked[0] = new File(getCatalinaHome(),
                                   "server" + File.separator + "classes");
            packed[0] = new File(getCatalinaHome(),
                                 "server" + File.separator + "lib");
            catalinaLoader =
                ClassLoaderFactory.createClassLoader(unpacked, packed,
                                                     commonLoader);

            unpacked[0] = new File(getCatalinaBase(),
                                   "shared" + File.separator + "classes");
            packed[0] = new File(getCatalinaBase(),
                                 "shared" + File.separator + "lib");
            sharedLoader =
                ClassLoaderFactory.createClassLoader(unpacked, packed,
                                                     commonLoader);
        } catch (Throwable t) {

            log("Class loader creation threw exception", t);
            System.exit(1);

        }

        Thread.currentThread().setContextClassLoader(catalinaLoader);

        // Load our startup class and call its process() method
        try {

            SecurityClassLoad.securityClassLoad(catalinaLoader);

            // Instantiate a startup class instance
            if (debug >= 1)
                log("Loading startup class");
            Class startupClass =
                catalinaLoader.loadClass
                ("org.apache.catalina.startup.Catalina");
            Object startupInstance = startupClass.newInstance();

            // Set the shared extensions class loader
            if (debug >= 1)
                log("Setting startup class properties");
            String methodName = "setParentClassLoader";
            Class paramTypes[] = new Class[1];
            paramTypes[0] = Class.forName("java.lang.ClassLoader");
            Object paramValues[] = new Object[1];
            paramValues[0] = sharedLoader;
            Method method =
                startupInstance.getClass().getMethod(methodName, paramTypes);
            method.invoke(startupInstance, paramValues);

            // Call the process() method
            if (debug >= 1)
                log("Calling startup class process() method");
            methodName = "process";
            paramTypes = new Class[1];
            paramTypes[0] = args.getClass();
            paramValues = new Object[1];
            paramValues[0] = args;
            method =
                startupInstance.getClass().getMethod(methodName, paramTypes);
            method.invoke(startupInstance, paramValues);

        } catch (Exception e) {
            System.out.println("Exception during startup processing");
            e.printStackTrace(System.out);
            System.exit(2);
        }

    }

那么执行这个mian 方法,那么tomcat 的源码在哪里呢?

具体为什么在这里,那么就要分析他的编译过程,下一篇就写下这个吧

posted @ 2021-07-14 16:23  张艳涛&java  阅读(78)  评论(0编辑  收藏  举报