import java.util.*;

import java.lang.Comparable;

/**

?* @desc 比較equals() 返回true 以及 返回false時， hashCode()的值。

?*

?* @author skywang

?* @emai kuiwu-wang@163.com

?*/

public class ConflictHashCodeTest2{

????public static void main(String[] args) {

????????// 新建Person對象，

????????Person p1 = new Person("eee", 100);

????????Person p2 = new Person("eee", 100);

????????Person p3 = new Person("aaa", 200);

????????Person p4 = new Person("EEE", 100);

????????// 新建HashSet對象

????????HashSet set = new HashSet();

????????set.add(p1);

????????set.add(p2);

????????set.add(p3);

????????// 比較p1 和 p2， 并打印它們的hashCode()

????????System.out.printf("p1.equals(p2) : %s; p1(%d) p2(%d)\n", p1.equals(p2), p1.hashCode(), p2.hashCode());

????????// 比較p1 和 p4， 并打印它們的hashCode()

????????System.out.printf("p1.equals(p4) : %s; p1(%d) p4(%d)\n", p1.equals(p4), p1.hashCode(), p4.hashCode());

????????// 打印set

????????System.out.printf("set:%s\n", set);

????}

????/**

?????* @desc Person類。

?????*/

????private static class Person {

????????int age;

????????String name;

????????public Person(String name, int age) {

????????????this.name = name;

????????????this.age = age;

????????}

????????public String toString() {

????????????return name + " - " +age;

????????}

????????/**

?????????* @desc重寫hashCode

?????????*/ ?

????????@Override

????????public int hashCode(){ ?

????????????int nameHash = ?name.toUpperCase().hashCode();

????????????return nameHash ^ age;

????????}

????????/**

?????????* @desc 覆蓋equals方法

?????????*/ ?

????????@Override

????????public boolean equals(Object obj){ ?

????????????if(obj == null){ ?

????????????????return false; ?

????????????} ?

????????????//如果是同一個對象返回true，反之返回false ?

????????????if(this == obj){ ?

????????????????return true; ?

????????????} ?

????????????//判斷是否類型相同 ?

????????????if(this.getClass() != obj.getClass()){ ?

????????????????return false; ?

????????????} ?

????????????Person person = (Person)obj; ?

????????????return name.equals(person.name) && age==person.age; ?

????????}

????}

}

結果：

p1.equals(p2) : true; p1(68545) p2(68545)
p1.equals(p4) : false; p1(68545) p4(68545)
set:[aaa - 200, eee - 100]

轉載于:https://www.cnblogs.com/chengshixiaonongming/p/10410571.html

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