java之Map

August 25, 2022

此篇为 Map，关于 Collection 及集合类概述，见此

Map

https://docs.oracle.com/javase/8/docs/api/java/util/Map.html

java

public interface Map<K, V> {
    int size();
    boolean isEmpty();
    boolean containsKey(Object key);
    boolean containsValue(Object value);
    V get(Object key);
    V put(K key, V value);
    V remove(Object key);
    void putAll(Map<? extends K, ? extends V> m);
    void clear();
    Set<K> keySet();
    Collection<V> values();
    Set<Map.Entry<K, V>> entrySet();
    interface Entry<K, V> {
        K getKey();
        V getValue();
        V setValue(V value);
        boolean equals(Object o);
        int hashCode();
        public static <K extends Comparable<? super K>, V> Comparator<Map.Entry<K, V>> comparingByKey();
        public static <K, V extends Comparable<? super V>> Comparator<Map.Entry<K, V>> comparingByValue();
        public static <K, V> Comparator<Map.Entry<K, V>> comparingByKey(Comparator<? super K> cmp);
        public static <K, V> Comparator<Map.Entry<K, V>> comparingByValue(Comparator<? super V> cmp);
        // ! 以下 API 自 java 17
        public static <K, V> Map.Entry<K, V> copyOf(Map.Entry<? extends K, ? extends V> e);
    }
    boolean equals(Object o);
    int hashCode();
    default V getOrDefault(Object key, V defaultValue);
    default void forEach(BiConsumer<? super K, ? super V> action);
    default void replaceAll(BiFunction<? super K, ? super V, ? extends V> function);
    default V putIfAbsent(K key, V value);
    default boolean remove(Object key, Object value);
    default boolean replace(K key, V oldValue, V newValue);
    default V replace(K key, V value);
    default V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction);
    default V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction);
    default V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction);
    default V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction);
    // ! 以下 API 自 java 9
    static <K, V> Map<K, V> of();
    static <K, V> Map<K, V> of(K k1, V v1, K k2, V v2,...省略, K k10, V v10);
    static <K, V> Map<K, V> ofEntries(Entry<? extends K, ? extends V>... entries);
    static <K, V> Entry<K, V> entry(K k, V v);
    // ! 以下 API 自 java 10
    static <K, V> Map<K, V> copyOf(Map<? extends K, ? extends V> map);
}

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