【Java】Map

今天用到了键-值对，于是想起了 Java 的 Map，由于之前并不很熟悉，就看了下源码，如下：

/*
* Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.util;
public interface Map<K,V> {
// Query Operations
int size();
boolean isEmpty();
boolean containsKey(Object key);
boolean containsValue(Object value);
V get(Object key);

// Modification Operations
V put(K key, V value);
V remove(Object key);

// Bulk Operations
void putAll(Map<? extends K, ? extends V> m);
void clear();

// Views
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();
}

// Comparison and hashing
boolean equals(Object o);
int hashCode();
}

PS: 看过后才清楚的知道 Map 是一个接口，而 HashMap 则是实现 Map 接口的一个类。而且觉得源码写得很美！以后要多看。

version: jdk1.7.0_79

Map 的遍历，示例代码：

Iterator entries = ReadFile.map.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry entry = (Map.Entry) entries.next();
String key = (String) entry.getKey();
String value = (String) entry.getValue();
System.out.print("key: " + key + ", " + "value: " + value + "\n");
}

参考：java中map,set的简单使用