📅 最后修改于: 2020-11-14 06:40:24 🧑 作者: Mango
java.util.WeakHashMap类是具有弱键的基于哈希表的Map实现。当不再使用其键时，WeakHashMap中的条目将由垃圾收集器自动删除。以下是有关WeakHashMap的要点-
空值和空键均受支持。
像大多数集合类一样，此类也不同步。
此类主要用于与其equals方法使用==运算符测试对象标识的关键对象一起使用。
WeakHashMap中的每个关键对象都间接存储为弱引用的引用。
此类是Java Collections Framework的成员。
以下是java.util.WeakHashMap类的声明-
public class WeakHashMap
extends AbstractMap
implements Map
这里
| Sr.No. | Constructor & Description |
|---|---|
| 1 |
WeakHashMap() This constructor is used to create an empty WeakHashMap with the default initial capacity (16) and load factor (0.75). |
| 2 |
WeakHashMap(int initialCapacity) This constructor is used to create an empty WeakHashMap with the given initial capacity and the default load factor (0.75). |
| 3 |
WeakHashMap(int initialCapacity, float loadFactor) This constructor is used to create an empty WeakHashMap with the given initial capacity and the given load factor. |
| 4 |
WeakHashMap(Map m) This constructor is used to create a new WeakHashMap with the same mappings as the specified map. |
| Sr.No. | Method & Description |
|---|---|
| 1 | void clear()
This method removes all of the mappings from this map. |
| 2 | boolean containsKey(Object key)
This method returns true if this map contains a mapping for the specified key. |
| 3 | boolean containsValue(Object value)
This method returns true if this map maps one or more keys to the specified value. |
| 4 | Set This method returns a Set view of the mappings contained in this map. |
| 5 | v get(Object key)
This method returns the value to which the specified key is mapped, or null if this map contains no mapping for the key. |
| 6 | boolean isEmpty()
This method returns true if this map contains no key-value mappings. |
| 7 | Set This method returns a Set view of the keys contained in this map. |
| 8 | v put(K key, V value)
This method associates the specified value with the specified key in this map. |
| 9 | void putAll(Map m)
This method copies all of the mappings from the specified map to this map. |
| 10 | v remove(Object key)
This method removes the mapping for a key from this weak hash map if it is present. |
| 11 | int size()
This method returns the number of key-value mappings in this map. |
| 12 | Collection This method returns a Collection view of the values contained in this map. |
此类从以下类继承方法-