//第四个参数："用户名,默认为空" 说明
flag.StringVar(&user, "u", "1", "用户名,默认为空")
flag.StringVar(&pwd, "pwd", "1", "密码,默认为空")
flag.StringVar(&host, "h", "localhost", "主机名,默认为localhost")
flag.IntVar(&port, "port", 3306, "端口号，默认为3306")
//这里有一个非常重要的操作,转换， 必须调用该方法
flag.Parse()
//输出结果
fmt.Printf("user=%v pwd=%v host=%v port=%v",
user, pwd, host, port)
flag.StringVar(&user, "u", "", "用户名")
flag.StringVar(&pwd, "pwd", "", "密码,默认为空")
flag.StringVar(&host, "h", "localhost", "主机名,默认为localhost")
flag.IntVar(&port, "port", 3306, "端口号,默认为3306")
flag.Parse()
fmt.Printf("user=%v pwd=%v host=%v port=%v", user, pwd, host, port)
