遍历key,value,key-value

package com.atguigu.exer;

import java.util.*;

/**
 * @author JessieWu
 * @create 2020-08-12  21:47
 */
public class Test {
    public static void main(String[] args) {
        //遍历key
        HashMap<String,Integer> map = new HashMap<>();
        map.put("wzq",12);
        map.put("wmn",123);
        map.put("qwe",125);
        map.put("wzadasq",712);
        map.put("wzadsdsaq",3312);
        Set<String> strings = map.keySet();
        Iterator<String> iterator = strings.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
        //遍历values
        Collection<Integer> coll = map.values();
        for(Integer c:coll){
            System.out.println(c);
        }

        //遍历key-value
        Set<Map.Entry<String,Integer>> entrySet = map.entrySet();
        Iterator<Map.Entry<String,Integer>> iterator1 = entrySet.iterator();
        while(iterator1.hasNext()){
            Map.Entry<String, Integer> next = iterator1.next();
            String key = next.getKey();
            Integer value = next.getValue();
            System.out.println(key + "--->" + value);
        }


    }


}