实现固定大小的hashMap（JAVA）

客官°小女子只卖身不卖艺 2023-10-11 11:59 32阅读 0赞

**1、创建一个固定大小的hashMap**

1 import java.util.LinkedHashMap;
     2 import java.util.Map;
     3 
     4 public class MaxSizeHashMap<K, V> extends LinkedHashMap<K, V> {
     5     private final int maxSize;
     6 
     7     public MaxSizeHashMap(int maxSize) {
     8         this.maxSize = maxSize;
     9     }
    10 
    11 
    12     //
    13     //Returns true if this map should remove its eldest entry. 
    14     //This method is invoked by put and putAll after inserting a new entry into the map. 
    15     //It provides the implementor with the opportunity to remove the eldest entry each time a new 
    16     //one is added. This is useful if the map represents a cache: 
    17     //    it allows the map to reduce memory consumption by deleting stale entries. 
    18     //
    19     @Override
    20     protected boolean removeEldestEntry(Map.Entry<K, V> eldest) {
    21         return size() > maxSize;
    22     }
    23 }

**2、使用固定大小的hashMap**

@Test
        public void testMaxSizeMap(){
            MaxSizeHashMap<String,String> map = new MaxSizeHashMap<>(10);
            for(int i=0;i<100;i++){
                map.put(""+i,""+i);
            }
            System.out.println(map.size());  //10  保留最后存入map的10个数据
        }

参考地址

[https://www.cnblogs.com/scottgu/p/4118428.html][https_www.cnblogs.com_scottgu_p_4118428.html]  
[https://blog.csdn.net/ClementAD/article/details/50596178][https_blog.csdn.net_ClementAD_article_details_50596178]

转载于:https://www.cnblogs.com/kiko2014551511/p/11527169.html

[https_www.cnblogs.com_scottgu_p_4118428.html]: https://www.cnblogs.com/scottgu/p/4118428.html
[https_blog.csdn.net_ClementAD_article_details_50596178]: https://blog.csdn.net/ClementAD/article/details/50596178