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  • java hashmap遍历顺序_史上最完整的集合类总结及hashMap遍历

    一.java集合类的比较:

    二、HashMap的遍历共有两种:

    1.利用entrySet 键值对映射:

    Map map = new HashMap();

    Iterator it = map.entrySet().iterator();

    while(it.hashNext()){
    Map.Entry s = (Map.Entry)it.next();

    System.out.println(s.getKey());

    System.out.println(s.getValue());

    }

    2.利用keySet:

    Map map = new HashMap();

    Iterator it = map.keySet().iterator();

    while(it.hasNext()){
    Object key = it.next();

    System.out.println(key);

    System.out.println(map.get(key));

    }

    LinkedHashMap的遍历,保证读取数据的顺序和put的顺序一致:

    /**

    • LinkedHashMap倒序

    • @author zzw

    */

    public class LinkedHashMapSort {
    public static void main(String[] args) {
    LinkedHashMap linkedhashmap = new LinkedHashMap();

    linkedhashmap.put("1","a");

    linkedhashmap.put("2","b");

    linkedhashmap.put("3","c");

    linkedhashmap.put("4","d");

    ListIterator> i=new ArrayList>

    (linkedhashmap.entrySet()).listIterator(linkedhashmap.size());

    while(i.hasPrevious()) {
    Map.Entry entry=i.previous();

    System.out.println(entry.getKey()+":"+entry.getValue());

    }

    }

    }
    ————————————————
    版权声明:本文为CSDN博主「荼蘼夜未央」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。
    原文链接:https://blog.csdn.net/weixin_34221599/article/details/114191381

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  • 原文地址:https://www.cnblogs.com/baicia/p/14606586.html
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