【HashSet：重写比较方法示例二】

package com.yjf.esupplier.common.test;

import java.util.HashSet;

/**
 * @author shusheng
 * @description
 * @Email shusheng@yiji.com
 * @date 2018/12/14 15:04
 */
public class DogDemo {
    /**
     * HashSet集合存储自定义对象并遍历，如果对象的成员变量值相同即为同一个对象
     * <p>
     * 注意了：
     * 你使用的是HashSet集合，这个集合的底层是哈希表结构
     * 而哈希表结构底层依赖:hashCode()和equals()方法
     * 如果你认为对象的成员变量相同即为同一个对象的话，你就应该重写这两个方法，这两个方法可以自动生成。
     */
    public static void main(String[] args) {

        //创建集合
        HashSet<Dog> hs = new HashSet<Dog>();

        //创建狗对象
        Dog d1 = new Dog("秦桧", 25, "红色", "男");
        Dog d2 = new Dog("高俅", 22, "黑色", "女");
        Dog d3 = new Dog("秦桧", 25, "红色", "男");
        Dog d4 = new Dog("秦桧", 20, "红色", "男");
        Dog d5 = new Dog("魏宗贤", 28, "败色", "男");
        Dog d6 = new Dog("魏宗贤", 28, "败色", "男");

        hs.add(d1);
        hs.add(d2);
        hs.add(d3);
        hs.add(d4);
        hs.add(d5);
        hs.add(d6);

        for (Dog d : hs) {
            System.out.println(d.getName() + "---" + d.getAge() + "---" + d.getColour() + "---" + d.getSex());
        }
    }
}

class Dog {
    private String name;
    private int age;
    private String sex;
    private String colour;

    public Dog() {
        super();
    }

    public Dog(String name, int age, String sex, String colour) {
        super();
        this.name = name;
        this.age = age;
        this.sex = sex;
        this.colour = colour;
    }

    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;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getColour() {
        return colour;
    }

    public void setColour(String colour) {
        this.colour = colour;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((colour == null) ? 0 : colour.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((sex == null) ? 0 : sex.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }

        Dog other = (Dog) obj;
        if (age != other.age) {
            return false;
        }
        if (colour == null) {
            if (other.colour != null) {
                return false;
            }
        } else if (!colour.equals(other.colour)) {
            return false;
        }

        if (name == null) {
            if (other.name != null) {
                return false;
            }
        } else if (!name.equals(other.name)) {
            return false;
        }

        if (sex == null) {
            if (other.sex != null) {
                return false;
            }
        } else if (!sex.equals(other.sex)) {
            return false;
        }

        return true;
    }

}