package test;

public class Test {

    public static void main(String[] args) {

        System.out.println("###############对象时比的都是地址################");

        TestObj t = new TestObj();

        TestObj t2 = new TestObj();

        System.out.println(t==t2);//false

        System.out.println(t.equals(t2));//false

        System.out.println("############基本类型[==]比的是值###########");

        int a=1;

        float b=1f;

        System.out.println(a==b);//true

        //  System.out.println(a.equals(b)); 写法错误

        System.out.println("##########Integer特殊(equals重写成比较值，但new时==还是比较地址)##########");

        Integer i1=0;

        Integer i2=0;

        System.out.println(i1==i2);//true

        System.out.println(i1.equals(i2));//true

        Integer i3 = new Integer(0);

        Integer i4 = new Integer(0);

        System.out.println(i3==i4);//false

        System.out.println(i3.equals(i4));//true

        System.out.println(i1==i3);//false

        System.out.println(i1.equals(i3));//true

        System.out.println(i4.equals(i2));//true

        int i5 = 0;

        System.out.println(i1.equals(i5));//true 和基本int类型比是比值

        System.out.println(i1==i5);//true 和基本int类型比也是比值

        System.out.println(i3.equals(i5));//true new的和基本int类型比是比值

        System.out.println(i3==i5);//true  new的和基本int类型比也是比值

        float f6 = 0f;//等同f6=0;

        System.out.println(i1.equals(f6));//false 注意结果不同说明equals的重写只是对int类型时是比值

        System.out.println(i1==f6);//true

        System.out.println(i3.equals(f6));//false 注意结果不同说明equals的重写只是对int类型时是比值

        System.out.println(i3==f6);//true  

        System.out.println("=======String特殊=======");

        String s1="a";

        String s2="a";

        System.out.println(s1==s2);

        System.out.println(s1.equals(s2));

        String s3 = new String("a");

        String s4 = new String("a");

        System.out.println(s3==s4);

        System.out.println(s3.equals(s4));

        System.out.println(s1==s3);

        System.out.println(s1.equals(s3));

        System.out.println(s4.equals(s2));

    }

}

/**

     * Compares this object to the specified object.  The result is

     * {@code true} if and only if the argument is not

     * {@code null} and is an {@code Integer} object that

     * contains the same {@code int} value as this object.

     *

     * @param   obj   the object to compare with.

     * @return  {@code true} if the objects are the same;

     *          {@code false} otherwise.

     */

    public boolean equals(Object obj) {

        if (obj instanceof Integer) {

            return value == ((Integer)obj).intValue();

        }

        return false;

    }