【HashMap：用对象作为KEY】

package com.yjf.esupplier.common.test;

import java.util.HashMap;
import java.util.Set;

/**
 * @author shusheng
 * @description 用对象作为KEY，重写比较方法
 * @Email shusheng@yiji.com
 * @date 2018/12/17 17:57
 */
public class MapDemo3 {
    public static void main(String[] args) {
        HashMap<Student, String> hm = new
                HashMap<Student, String>();

        //创建学生对象
        Student s1 = new Student("貂蝉", 27);
        Student s2 = new Student("王昭君", 28);
        Student s3 = new Student("西施", 29);
        Student s4 = new Student("杨玉环", 26);
        Student s5 = new Student("杨玉环", 26);

        //添加元素
        hm.put(s1, "100");
        hm.put(s2, "101");
        hm.put(s3, "102");
        hm.put(s4, "103");
        hm.put(s5, "104");

        //遍历
        Set<Student> set = hm.keySet();
        for (Student key : set) {
            String value = hm.get(key);
            System.out.println(key.getName() + "---" + key.getAge()
                    + "---" + value);
        }
    }
}

class Student{
    private String name;
    private int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public int hashCode() {
        return this.name.hashCode() + this.age * 113;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (!(obj instanceof Student)) {
            return false;
        }

        Student s = (Student) obj;
        return this.name.equals(s.name) && this.age == s.age;
    }
}

执行结果：

杨玉环---26---104
貂蝉---27---100
王昭君---28---101
西施---29---102