关于Integer比较问题

 public class Test {
     public static void main(String[] args) {
         Integer a=127;
         Integer b=127;
         System.out.println(a==b);
         System.out.println(a.equals(b));
         Integer c=128;
         Integer d=128;
         System.out.println(c==d);
         System.out.println(c.equals(d));
         Integer e=0;
         Integer f=null;
         System.out.println(e==f);
         System.out.println(e.equals(f));
     }
 }