LinkedHashMap集合
java.util.LinkedHashMap entends HashMap
Map 接口的哈希表和链接列表实现,具有可预知的迭代顺序。
- 底层原理:
哈希表+链表(记录元素的顺序)
public class Demo01LinkedHashMap {
public static void main(String[] args) {
HashMap<String,String> map = new HashMap<>();
map.put("a","a");
map.put("c","c");
map.put("b","b");
map.put("a","d");
System.out.println(map);// key不允许重复,无序 {a=d, b=b, c=c}
LinkedHashMap<String,String> linked = new LinkedHashMap<>();
linked.put("a","a");
linked.put("c","c");
linked.put("b","b");
linked.put("a","d");
System.out.println(linked);// key不允许重复,有序 {a=d, c=c, b=b}
}
}