HashMap的初步应用类

package day18.HashMap;

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

/**
 * 描述:
 * 这是一个HashMap的初步应用类
 *
 * @outhor 71948
 * @create 2017-10-06 21:37
 */
public class Demo1_HashMap {
    public static void main(String[] args) {
        Map
 
   map = new HashMap<>();
//        map.put("zhang",12);
//        map.put("zhang1",13);
        Integer i1 = map.put("张三",21);
        Integer i2 = map.put("张三",22);
        Integer i3 = map.put("李四",22);
        Integer i4 = map.put("王五",21);

        System.out.println(map);
        System.out.println(i1);
        System.out.println(i2);
        System.out.println(i3);
        System.out.println(i4);
    }
}