Integer a = new 127;
Integer b = new 127;
System.out.println(a==b);//ture 常量池byte（-127-127之间）integer b地址不会发生改变；
System.out.println(a.equals(b));//true
System.out.println("---------------------");
Integer a = new 128;
Integer b = new 128;
System.out.println(a==b);//false 常量池byte（-127-127之间）integer b地址发生了改变；
System.out.println(a.equals(b));//true