由tomcat启动想到的

      @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
      
      
    

      
              先说echo off就是说不显示bat文件的内容只显示执行结果，加上@后连echo off也不显示了。下面看17行
      
    

                     if "%OS%" == "Windows_NT" setlocal
    

          双%% 是从环境变量里读取信息，下来需要看看setlocal这个命令做了些什么操作，下面看一下
    

      在microsoft网站上对于setlocal的讲解：
    

              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.
      

              set "CURRENT_DIR=%cd%"