java中HashMap.values()转为ArrayList()问题

HashMap.values()转为ArrayList()

由于HashMap.values()只能转为Collection集合所以需要转为ArrayList的话可以用一下代码

ArrayList<Integer> al = new ArrayList(hash.values());

map.values()转为List和ArrayList的复制

package List;

import java.util.*;

public class List4 {
 public static void main(String[] args) {
 List<Integer> list = new ArrayList<>();
 list.add(7);
 list.add(8);
 list.add(9);
 list.add(10);
 list.add(11);
 System.out.println("list = " + list);
 ArrayList<Integer> list1 = new ArrayList<>(list);
 System.out.println("list1 = " + list1);

 Map<Integer, String> map = new HashMap<>();
 map.put(1, "4536117005899");
 map.put(2, "2022032600002");
 map.put(3, "4536117001860");
 map.put(4, "202203260000");

 //System.out.println("map = " + map.values());
 Collection<String> values = map.values();
 //map.values()转为List
 ArrayList<String> maps = new ArrayList<>(values);
 System.out.println("maps = " + maps);
 }
}

在这里插入图片描述

总结

作者:So_Band原文地址:https://blog.csdn.net/So_Band/article/details/89504741

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