Integer a = 1;
Integer b = 2;
Long c = 3L;
Integer d = 333;
Integer e= 333;
System.out..println(c==a+b);
System.out..println(c.equal s(a+b));
System.out..println(d==e);
System.out..println(d.equals(e));
原文：http://www.cnblogs.com/oldfish/p/3559977.html