利用LinkedHashMap生成缓存类

最新推荐文章于 2025-01-30 10:09:16 发布

iteye_2002

最新推荐文章于 2025-01-30 10:09:16 发布

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分类专栏： java 文章标签： java

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1. LRU缓存

LRU是Least Recently Used 近期最少使用算法

import java.util.LinkedHashMap;
import java.util.Map;

public class LRUCache<K, V> extends LinkedHashMap<K, V> {
	private static final long serialVersionUID = -1882071901467368406L;
	static final int DEFAULT_INITIAL_CAPACITY = 16;
	static final float DEFAULT_LOAD_FACTOR = 0.75f;
	static final int DEFAULT_CACHE_SIZE = 1024;

	private final int cacheSize;

	public LRUCache() {
		this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CACHE_SIZE);
	}

	public LRUCache(int capacity, float loadFactor, int cacheSize) {
		super(capacity, loadFactor, true);
		this.cacheSize = cacheSize;
	}

	protected boolean removeEldestEntry(Map.Entry<K,V> eldest) {
		return size() > cacheSize;
	}
}

1. FIFO缓存

import java.util.LinkedHashMap;

public class CommonCache<K, V> extends LinkedHashMap<K, V> {

    /** UID。 */
    private static final long serialVersionUID = 1L;

    /** 默认缓存SIZE。 */
    private static final int DEFAULT_CACHE_SIZE = 1024;

    /** 缓存SIZE。 */
    private int cacheSize = DEFAULT_CACHE_SIZE;

    /**
     * 构造方法。
     */
    public CommonCache() {
    }

    /**
     * @return cacheSize
     */
    public int getCacheSize() {
        return cacheSize;
    }

    /**
     * @param cacheSize
     */
    public void setCacheSize(int cacheSize) {
        this.cacheSize = cacheSize;
    }

    @Override
    protected boolean removeEldestEntry(java.util.Map.Entry<K, V> eldest) {
        return size() > cacheSize;
    }
}