Map.Entry

package MapTest;

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

public class EntryTest {


    public static void main(String[] args){
        HashMap<String, String> map = new HashMap<>();
        map.put("1","kangkang");
        map.put("2","xiaowang");
        //静态方法调用非静态方法--》实例化一个对象--》通过对象调用里面的方法
        EntryTest entryTest = new EntryTest();
//        entryTest.MapEntry(map);
        entryTest.entrySetTest(map);
            }
    //map.entry
    public  void MapEntry(Map map){

        //获取map的值
        //获取k-v对集合
        Set<Map.Entry<String, String>> entries = map.entrySet();
        if(entries != null) {
            //得到迭代器
            Iterator<Map.Entry<String, String>> iterator = entries.iterator();
            //开始迭代
            while (iterator.hasNext()) {
                //得到一个Map.Entry实例化的对象
                Map.Entry<String, String> student = iterator.next();
                //获取key和value
                String id = student.getKey();
                String name = student.getValue();
                System.out.println(id + "==" + name);
            }
        }
    }
    //keyset
    public void entrySetTest(Map map){
        //获取key集合,存储的是所有的id
        Set set = map.keySet();
        if(set != null){
            Iterator iterator = set.iterator();
            while (iterator.hasNext()){
                Object id = iterator.next();
                //这里需要重复调用map.get()方法
                Object name = map.get(id);
                System.out.println(id + "==" + name);

            }

        }

    }

}