java 基础笔记--Map

时间：2017-09-07 23:00:55 阅读：252 评论：0 收藏：0 [点我收藏+]

标签：默认接口 other name java 基础 system etc 选择 result

在Java的世界里，万物皆为对象，那么Map是一个接口!哈哈

举个例子：

Map<User,String> map=new HashMap<User, String>();

其中User类

package com.map;

public class User {

    private int age;
    private String name;
    public int getAge() {
        return age;
    }
    
    public User(){
        super();
    }
    
    /**
     * 
     * @param age
     * @param name
     */
    public User(int age,String name){
        super();
        this.age=age;
        this.name=name;
    }
    
    public void setAge(int age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @Override
    public int hashCode() {
        System.out.println("运行了hashCode");
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((name == null) ? 0 : name.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;
        User other = (User) obj;
        if (age != other.age)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
    
    
    
}

运行

package com.map;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class MapTest {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        User user=new User(10,"小明");
        User user1=new User(12,"小里");
        Map<User,String> map=new HashMap<User, String>();
        map.put(user, "小明");
        map.put(user1, "kk");
        
        Iterator<User> iter=map.keySet().iterator();
        while(iter.hasNext()){
            User user2=iter.next();
            String name=map.get(user2);
        }
        
        
        
    }

}