Way To JAVA-1.1编译之自动装箱和拆箱

public static void main(String[] args){
    Integer a =1;
    Integer b =2;
    Integer c =3;
    Integer d =3;
    Integer e =321;
    Integer f =321;
    Long g = 3L;
    System.out.println(c==d);//true
    System.out.println(e==f);//false
    System.out.println(c==(a+b));//true
    System.out.println(c.equals(a+b));//true
    System.out.println(g==(a+b));//true
    System.out.println(g.equals(a+b));//false
}

public static void main(String[] args) {
    Integer a = Integer.valueOf(1);
    Integer b = Integer.valueOf(2);
    Integer c = Integer.valueOf(3);
    Integer d = Integer.valueOf(3);
    Integer e = Integer.valueOf(321);
    Integer f = Integer.valueOf(321);
    Long g = Long.valueOf(3L);
    System.out.println(c == d);//这个时候比较的是地址
    System.out.println(e == f);
    System.out.println(c.intValue() == a.intValue() + b.intValue());
    System.out.println(c.equals(Integer.valueOf(a.intValue() + b.intValue())));
    System.out.println(g.longValue() == (long)(a.intValue() + b.intValue()));
    System.out.println(g.equals(Integer.valueOf(a.intValue() + b.intValue())));
}