（一）startup.bat

　　那么startup.bat（// TODO startup.sh暂缓）启动后发生了什么呢？

 @echo off
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 rem limitations under the License.

 if "%OS%" == "Windows_NT" setlocal
 rem ---------------------------------------------------------------------------
 rem Start script for the CATALINA Server
 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

　　line1　　@echo off　　@关闭本命令回显，echo off命令是关闭输出所执行的批处理操作

　　line17　　if "%OS%" == "Windows_NT"　　setlocal　　如果有OS这个环境变量且值为Windows_NT，开始设置本地环境变量。其中setlocal命令的解释是：Starts localization of environment variables in a batch file. Localization continues until a matching endlocal command is encountered or the end of the batch file is reached. 即在批处理文件中开始设置本地化环境变量，这些变量在遇到与之（setlocal）对应的endlocal命令或者bat文件结束前一直有效。刚才发现电脑上另一个版本的tomcat（7.0.67）中已经取消了OS变量的判断而直接setlocal。

　　line23-35　　Guess CATALINA_HOME if not defined，找CATALINA_HOME这个变量，判断catalina.bat是否存在。

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

　　line23　　set "CURRENT_DIR=%cd%"　　CURRENT_DIR就是启动后第一个临时环境变量，这个环境变量的值是%cd%，"%cd%" 获取的是bat文件执行的当前目录，cd = current_dir的缩写，即C:\tool\apache-tomcat-7.0.67\bin。

　　line24　　if not "%CATALINA_HOME%" == "" goto gotHome　　如果设置了CATALINA_HOME环境变量，goto gotHome节点，但我估计开发很少有设置这个环境变量的（反正我从不）；没有这个变量的话继续。

　　line25　　set "CATALINA_HOME=%CURRENT_DIR%"　　设置CATALINA_HOME（算是又一个临时环境变量）为当前bat文件执行目录, 即C:\tool\apache-tomcat-7.0.67\bin。

　　line 26　　if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome　　如果%CATALINA_HOME%E\bin\下的catalina.bat存在的话，goto okHome节点。默认安装的tomcat里catalina.bat和startup.bat都在%CATALINA_HOME%E\bin\下。

　　line27　　cd ..　　如果在%CATALINA_HOME%E\bin\没有catalina.bat文件，回到父目录即C:\tool\apache-tomcat-7.0.67。

　　line28　　set "CATALINA_HOME=%cd%"　　然后改变CATALINA_HOME=C:\tool\apache-tomcat-7.0.67。

　　line29　　cd "%CURRENT_DIR%"　　回到C:\tool\apache-tomcat-7.0.67\bin。

　　line31　　if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome　　再次判断catalina.bat是否存在，如果存在goto okHome节点；不存在执行line32-33的输出，然后goto end节点，本次批处理结束。

　　line37　　set "EXECUTABLE=%CATALINA_HOME%\bin\catalina.bat"　　设置executable节点

　　line39-44　　再次判断%CATALINA_HOME%\bin\catalina.bat是否存在，如果存在goto okExec节点；不存在goto end节点，本次批处理结束。

　　line46-53　　设置CMD_LINE_ARGS　

set CMD_LINE_ARGS=
:setArgs
if ""%1""=="""" goto doneSetArgs
set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
shift
goto setArgs
:doneSetArgs

　　line47-48　　将: setArgs节点下的返回结果赋值给CMD_LINE_ARGS变量。

　　line49-52　　如果%1也就是第一个参数为空，goto doneSetArgs；否则循环所有的参数，将所有的参数加上一个空格后拼接在一起，赋值给CMD_LINE_ARGS变量，全部参数处理完后执行line56

shift命令    批处理文件中可引用的参数为%0~%9，%0是指批处理文件的本身，也可以说是一个外部命令: %1~%9是批处理参数，也称形参: 而替换形参的实参若超过了批处理文件中所规定数值(9个)且想在批处理文件中应用这些实参的话，shift命令可以帮你实现！它更改批处理文件中可替换参数的位置，shift [/n] n的取值是[0,8],且为整数；[/n]为可选参数，当赋予n某个值时，就意味着命令从第n个参数开始移位；当n赋予的值为0,1或不带有任何命令选项的shift时，则表示批处理文件中替换参数左移一个位置，后面的替换参数陆续填补上去，直至可替换参数为空。

shift命令

　　line56　　call "%EXECUTABLE%" start %CMD_LINE_ARGS%　　调用EXECUTABLE参数为start和上边拼接CMD_LINE_ARGS（可能为空）。

　　至此，startup.bat结束，可以看出它主要的目的是找到并启动catalina.bat。