Java | 基础归纳 | Map.Entry<String, String>

 public class Test {
     private static Map<String,String> student;

     private static void init() {
         student = new LinkedHashMap<String,String>();
         student.put("16010001", "tom");
         student.put("16010002", "tony");
         student.put("16010003", "j");
         student.put("16010004", "yy");
     }

     public static void main(String[] args) {
         init();
          String key = null;
          Scanner stdin = new Scanner(System.in);
          System.out.println("Choose a SchoolId:");
          for(Map.Entry<String, String> stu:student.entrySet()) {
              System.out.println(stu.getKey()+"\t" + stu.getValue());
          }
          while(key == null) {
               key = stdin.nextLine();
               if (student.get(key) == null) {
                     System.out.println("Invalid choice!");
                     key = null;
                 }
          }

          System.out.println("Success!");
     }
 }