J250511/01-JavaSE阶段代码/J20250723/Demo06_Map02.java

package J20250723;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * @author WanJl
 * @version 1.0
 * @title Demo06_Map02
 * @description
 * @create 2025/7/23
 */
public class Demo06_Map02 {
    public static void main(String[] args) {
        Map<String,String> map=new HashMap<>();
        map.put("1001","张三");
        map.put("1002","李四");
        map.put("1003","王五");
        map.put("1004","赵六");
        map.put("1005","张十三");
        map.put("1006","张二十三");

        String s = map.get("1005");
        System.out.println("key是1005的value是"+s);
        //获取所有的key的集合
        Set<String> set = map.keySet();
        for (String s1 : set){
            System.out.println(s1);
        }
        //获取所有的value的集合
        Collection<String> values = map.values();
        for (String s2:values){
            System.out.println(s2);
        }

        //获取键值对对象的集合  通过entrySet遍历键值对集合
        Set<Map.Entry<String, String>> entries = map.entrySet();
        for (Map.Entry<String,String> e:entries){
            System.out.println("键："+e.getKey());
            System.out.println("值："+e.getValue());
        }

        System.out.println("---------------------------------");
        //遍历Map集合   --通过keySet()进行遍历
        //先获取所有键的集合
        Set<String> keySet = map.keySet();
        for (String key: keySet){
            //根据键获取值
            String value = map.get(key);
            System.out.println(key+"->"+value);
        }
    }
}