【Map集合的使用】

package com.yjf.esupplier.common.test;

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

/**
 * @author shusheng
 * @description Map集合的使用
 * @Email shusheng@yiji.com
 * @date 2018/12/17 16:29
 */
public class MapDemo1 {

    public static void main(String[] args) {
        // 创建集合
        Map<String, String> map = new HashMap<String, String>();

        //添加元素
        System.out.println("map:" + map.put("文章", "马伊琍"));
        System.out.println("map:" + map.put("文章", "姚笛"));
        map.put("邓超", "孙俪");
        map.put("黄晓明", "杨颖");
        map.put("周杰伦", "昆凌");
        map.put("刘恺威", "杨幂");
        System.out.println("map:" + map);

        //长度
        System.out.println("size:" + map.size());

        //删除功能
        System.out.println("remove:" + map.remove("黄晓明"));
        System.out.println("remove:" + map.remove("黄海波"));

        //判断功能
        System.out.println("containsKey:" + map.containsKey("黄晓明"));
        System.out.println("containsKey:" + map.containsKey("周杰伦"));
        System.out.println("containsValue:" + map.containsValue("杨幂"));
        System.out.println("containsValue:" + map.containsValue("张三"));

        //删除功能
        map.clear();
        System.out.println("isEmpty:" + map.isEmpty());

        //输出集合名称
        System.out.println("map:" + map);
    }

}

打印结果：

map:null
map:马伊琍
map:{邓超=孙俪, 文章=姚笛, 周杰伦=昆凌, 黄晓明=杨颖, 刘恺威=杨幂}
size:5
remove:杨颖
remove:null
containsKey:false
containsKey:true
containsValue:true
containsValue:false
isEmpty:true
map:{}