安装了jdk1.7，有错误提示

import java.util.Scanner;

public class Who {

public static void main(String[] args) {

Scanner we = new Scanner(System.in);

System.out.println("请输入1-7之间的数字：");

String w = we.next();

switch (w) {

case "Mon":

System.out.println("星期一");break;

case "Tue":

System.out.println("星期二");break;

case "Wed":

System.out.println("星期三");break;

case "Thu":

System.out.println("星期四");break;

case "Fir":

System.out.println("星期五");break;

case "Sat":

System.out.println("星期六");break;

case "Sun":

System.out.println("星期日");break;

default:

System.out.println("该数字超出了1-7的范围！");

}

}

}