Java集合框架怎样利用WeakHashMap处理缓存_Java集合框架弱引用映射的应用技巧

WeakHashMap

WeakHashMap

WeakHashMap

WeakHashMap

WeakHashMap

WeakHashMap

import java.util.WeakHashMap;

public class WeakHashMapCache {

    private static WeakHashMap<String, Object> cache = new WeakHashMap<>();

    public static Object get(String key) {
        return cache.get(key);
    }

    public static void put(String key, Object value) {
        cache.put(key, value);
    }

    public static void main(String[] args) throws InterruptedException {
        String key1 = new String("data1");
        String key2 = new String("data2");

        cache.put(key1, "value1");
        cache.put(key2, "value2");

        System.out.println("Cache size: " + cache.size()); // Output: Cache size: 2

        key1 = null; // key1不再有强引用

        System.gc(); // 触发垃圾回收

        Thread.sleep(2000); // 等待垃圾回收完成

        System.out.println("Cache size after GC: " + cache.size()); // Output: Cache size after GC: 1 (或者0，取决于GC的时机)
    }
}

key1

null

key1

WeakHashMap

WeakHashMap

WeakHashMap

HashMap

HashMap

HashMap

WeakHashMap

WeakHashMap

HashMap

WeakHashMap

WeakHashMap

ConcurrentModificationException

WeakHashMap

WeakHashMap

WeakHashMap

WeakHashMap

get()

put()

WeakHashMap

WeakHashMap

HashMap