Integer-int-Long-long总结

TODO: 找时间总结一下

Integer == cashe 问题

Integer 赋值问题

https://blog.csdn.net/qiuwenjie123/article/details/80153206

Long 和int，long比较

Long a = 1L;
System.out.println(a);
System.out.println(a == 1);
System.out.println(a == 1L);//1L是long不是Long
System.out.println(a.equals(1));//Long和int比较，false
System.out.println(a.equals(1L));

System.out.println();
Long b = 1L;
System.out.println(a == b);
System.out.println();
a = 1111L;
System.out.println(a);
System.out.println(a == 1111);
System.out.println(a == 1111L);
System.out.println(a.equals(1111));
System.out.println(a.equals(1111L));
System.out.println();
b = 1111L;
System.out.println(a == b);

System.out.println();

integer自动装箱 自动拆箱

Integer a1 = 10;
Integer a2 = 10;
Integer a3 = 1000;
Integer a4 = 1000;
System.out.println(a1 == a2);//true
System.out.println(a3 == a4);//false 缓存原因

int a =3;
Integer b = 4;//调了valueof方法
Integer c = 5;
Integer d = 6;
System.out.println(a == b);//调了b.intvalue
System.out.println(b == a);//调了b.intvalue
System.out.println(d == b);//直接比较两个对象，即地址（注意缓存）
System.out.println(d == b+c);//调了三次intvalue，说明这时候是int的比较，而不是Integer的比较
d > b;//这个也intvalue两次？