Apache-common 包之 common-cli 笔记

 

 

The Apache Commons CLI library provides an API for parsing command line options passed to programs. It's also able to print help messages detailing the options available for a command line tool.

Commons CLI supports different types of options:

• POSIX like options (ie. tar -zxvf foo.tar.gz)
• GNU like long options (ie. du --human-readable --max-depth=1)
• Java like properties (ie. java -Djava.awt.headless=true -Djava.net.useSystemProxies=true Foo)
• Short options with value attached (ie. gcc -O2 foo.c)
• long options with single hyphen (ie. ant -projecthelp)

CLI 即Command Line Interface，也就是"命令行接口"，它为Java 程序访问和解析命令行
参数提供了一种统一的接口。

主要处理java启动时,输入命令行的
纯java编译完*.class以后,会通过,下面命令运行带main的类
java 类名
打成jar包的则通过下面命令(带main方法)
java –jar 包名.jar
在eclipse下运行则需要通过Run as /runConfigurations/Arguments来进行命令行参数配置

参数的配置和我们常用的命令一样,横杠+参数名+空格+参数值
-参数名 参数值
然后java会根据main方法中 String[] args来取得命令行参数

通过使用commons-cli则可以很容易的访问参数，而不必去循环String[] args

package test.common.cli; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.commons.cli.PosixParser; /* 输入参数 -c code -t time 运行结果: code null */ public class CliTest { /** * @param args * @throws ParseException */ public static void main(String[] args)throws ParseException { Options options = new Options(); options.addOption("t", false, "display current time"); //参数不可用 options.addOption("c", true, "country code"); //参数可用 CommandLineParser parser = new PosixParser(); CommandLine cmd = parser.parse(options, args); if (cmd.hasOption("c")) { String countryCode = cmd.getOptionValue("c"); System.out.println(countryCode); } if (cmd.hasOption("t")) { String countryCode = cmd.getOptionValue("t"); System.out.println(countryCode); } } }

 

 

自动生成帮助声明:

// automatically generate the help statement HelpFormatter formatter = new HelpFormatter(); formatter.printHelp( "ant", options );

打印出来信息:

usage: ant -D <property=value> use value for given property -buildfile <file> use given buildfile -debug print debugging information -emacs produce logging information without adornments -file <file> search for buildfile towards the root of the filesystem and use it -help print this message -listener <classname> add an instance of class as a project listener -logger <classname> 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

 

参考网址：

    http://commons.apache.org/cli/

    http://phl.javaeye.com/blog/730737

    http://blog.youkuaiyun.com/socoolfj/archive/2005/12/01/541429.aspx