【JavaDemo】使用Entry遍历含自定义类的Map集合

短命女 2022-06-07 12:51 131阅读 0赞

> **含有自定义类的Map遍历 Demo2**

*    
    
 *  此Demo演示方法2：获取键值对对象Entry，然后用Entry分别键获取键和值。
 *  Map含有自定义类Singer。

> **自定义类Singer**

//歌手类
    public class Singer { 
    private String name;
    private String songName;
    public Singer(String name, String songName) {
        super();
        this.name = name;
        this.songName = songName;
    }
    public Singer() {
        super();
        // TODO Auto-generated constructor stub
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSongName() {
        return songName;
    }
    public void setSongName(String songName) {
        this.songName = songName;
    }
    @Override
    public String toString() {
        return "Singer [name=" + name + ", songName=" + songName + "]";
    }
    
    
    }

> **遍历类MapDemo2**

import java.util.HashMap;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.Set;
    
    /* * 使用Map遍历自定义类型 * 遍历方式：方法2，取出Map中所有的键值对对象Entry，根据Entry对象获取key和value。 */
    public class MapDemo2 { 
    
        public static void main(String[] args) {
    
            //定义Singer对象
            Singer s1 = new Singer("田馥甄","小幸运");
            Singer s2 = new Singer("孙燕姿","天黑黑");
            Singer s3 = new Singer("周杰伦","晴天");
            Singer s4 = new Singer("不 才","你有没有见过他");
    
            //定义一个Map
            Map<String,Singer> map = new HashMap<>();
    
            //将Singer对象添加到Map中
            map.put("001", s1);
            map.put("002", s2);
            map.put("003", s3);
            map.put("004", s4);
    
            //获取Entry对象
            Set<Entry<String, Singer>> entrySet = map.entrySet();
    
            //打印标题
            System.out.println("\t\t"+"编号"+"\t\t"+"姓名"+"\t\t\t\t"+"歌曲");
    
            //遍历每个Entry对象，通过Entry对象获取对应的歌手姓名和歌曲名称
            for (Entry<String, Singer> entry : entrySet) {
    
                System.out.println("\t\t"+entry.getKey()+"\t\t"+entry.getValue().getName()+"\t\t"+entry.getValue().getSongName());
            }
    
        }
    
    }