http://hao.jobbole.com/jcommander/
http://jcommander.org/#_overview
https://github.com/cbeust/jcommander

https://github.com/viakiba/springboot/tree/master/springboot_jcommander

<dependency>
			<groupId>com.beust</groupId>
			<artifactId>jcommander</artifactId>
			<version>LATEST</version>
</dependency>

@Parameters(separators = "= ")
// Parameters 用在类名上，separators的值用于分割key和value可以自定义。
public class CommandBean {
    //放在属性上 names 指定key的名字可以多个 required 标识此参数必须传入 description 此命令的表述  hiden如果为true 则不会显示在usage提示中。
    @Parameter(names = {"-p", "-port", "--port"}, required = true,
            description = "run mode. The agent/monitor modes are available.",hiden = true)
    public int port;

    @Parameter(names = {"-c", "-contexts", "--contexts"}, required = true,
            description = "run mode. The agent/monitor modes are available.")
    public String contexts;

    //略
}

// java -jar xxx -p=8005 -c=contextvalue
public static void main(String[] args) {
		//处理命令
		CommandBean commandBean = new CommandBean();
		JCommander jCommander = new JCommander(commandBean);
		try{
			jCommander.setProgramName("JcommanderApplication");
			jCommander.setAcceptUnknownOptions(true);
			jCommander.parse(args);
			System.out.println(commandBean.port);
		}catch (Exception e){
      //命令不对 或者不全 required为true的没有输入 usage 方法会输出命令提示，name / description 的内容会格式化输出。
			jCommander.usage();
			e.printStackTrace();
		}
    //此时 commandBean 这个变量的属性都会被传入的参数赋值。
    System.out.println(commandBean.toString())
}