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  一. common-cli是命令行工具包:包括三个阶段:

1. 定义命令行选项

2. 解析命令行选项

3.解释命令行选项

二. 定义阶段:

Options类是Option类的集合

解析阶段:

CommandLineParser类为命令行解析类,解析返回CommandLine类

解释阶段:

查询CommandLine根据不同组合进行不同分支处理

三. 例子:

// create the command line parserCommandLineParser parser = new PosixParser();// create the OptionsOptions options = new Options();options.addOption( "a", "all", false, "do not hide entries starting with ." );options.addOption( "A", "almost-all", false, "do not list implied . and .." );options.addOption( "b", "escape", false, "print octal escapes for nongraphic "                                         + "characters" );options.addOption( OptionBuilder.withLongOpt( "block-size" )                                .withDescription( "use SIZE-byte blocks" )                                .withValueSeparator( '=' )                                .hasArg()                                .create() );options.addOption( "B", "ignore-backups", false, "do not list implied entried "                                                 + "ending with ~");options.addOption( "c", false, "with -lt: sort by, and show, ctime (time of last "                                + "modification of file status information) with "                               + "-l:show ctime and sort by name otherwise: sort "                               + "by ctime" );options.addOption( "C", false, "list entries by columns" );String[] args = new String[]{ "--block-size=10" };try {    // parse the command line arguments    CommandLine line = parser.parse( options, args );    // validate that block-size has been set    if( line.hasOption( "block-size" ) ) {        // print the value of block-size        System.out.println( line.getOptionValue( "block-size" ) );    }}catch( ParseException exp ) {    System.out.println( "Unexpected exception:" + exp.getMessage() );}

四. 自动生成帮助声明:

// automatically generate the help statement

打印出来信息:

usage: ant-D 
   
         use value for given property-buildfile 
    
            use given buildfile-debug                  print debugging information-emacs                  produce logging information without adornments-file 
     
                  search for buildfile towards the root of the                        filesystem and use it-help                   print this message-listener 
      
          add an instance of class as a project listener-logger 
       
             the class which it to perform logging-projecthelp            print project help information-quiet                  be extra quiet-verbose                be extra verbose-version                print the version information and exit
       
      
     
    
   

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