常用的遍历map的方法

常用的遍历map的方法

package com.lxh.config.utils;

import java.util.*;

/** * @ClassName: commonUtil * @Author: lxh * @Description: 公共方法工具类 * @Date: 2022/4/14 14:53 */
public class CommonMethods {
    

    public static void main(String[] args) {
    
        Map<String, Object> map = new LinkedHashMap<>();
        map.put("id", 1);
        map.put("name", "lxh");
        map.put("age", 18);
        getMap(1, map);
        getMap(2, map);
        getMap(3, map);
        getMap(4, map);
        getMap(5, map);
    }

    /** * 遍历map */
    public static void getMap(Integer type, Map<String, Object> map) {
    
        if (type == 1) {
    
            System.out.println("============通过map.keySet()的key获取value===========");
            Set<String> set = map.keySet();
            set.forEach(item -> {
    
                System.out.println(item + ": " + map.get(item));
            });
        } else if (type == 2) {
    
            System.out.println("============通过map.entrySet()的实体去获取key跟value===========");
            Set<Map.Entry<String, Object>> entrySet = map.entrySet();
            entrySet.forEach(item -> {
    
                System.out.println(item.getKey() + ": " + item.getValue());
            });
        } else if (type == 3) {
    
            System.out.println("=============通过迭代器获取key跟value==========");
            Set<Map.Entry<String, Object>> entrySet = map.entrySet();
            Iterator<Map.Entry<String, Object>> iterator = entrySet.iterator();
            while (iterator.hasNext()) {
    
                Map.Entry<String, Object> entry = iterator.next();
                System.out.println(entry.getKey() + ": " + entry.getValue());
            }
        } else if (type == 4) {
    
            System.out.println("============通过map.values()获取value，不能获取key===========");
            map.values().forEach(System.out::println);
        } else if (type == 5) {
    
            System.out.println("============通过lambda表达式获取key跟value===========");
            map.forEach((key, value) -> System.out.println(key + ": " + value));
        }
    }
}