java 集合之 Map

蔚落 2023-07-25 08:56 27阅读 0赞

# TreeMap #

<table> 
 <tbody> 
 <tr> 
 <th>Modifier and Type</th> 
 <th>Method and Description</th> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#ceilingEntry-K-" rel="nofollow">ceilingEntry</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回与大于或等于给定键的最小键相关联的键值映射，如果没有此键，则&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#ceilingKey-K-" rel="nofollow">ceilingKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回大于或等于给定键的&nbsp;<code>null</code>键，如果没有此键，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#clear--" rel="nofollow">clear</a>()</code> 从这张地图中删除所有的映射。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#clone--" rel="nofollow">clone</a>()</code> 返回此&nbsp;<code>TreeMap</code>实例的浅拷贝。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Comparator.html" rel="nofollow">Comparator</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#comparator--" rel="nofollow">comparator</a>()</code> 返回用于订购此地图中的键的比较器，或<code>null</code>如果此地图使用其键的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Comparable.html" rel="nofollow">natural ordering</a>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#containsKey-java.lang.Object-" rel="nofollow">containsKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 如果此映射包含指定键的映射，则返回&nbsp;<code>true</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#containsValue-java.lang.Object-" rel="nofollow">containsValue</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;value)</code> 如果此地图将一个或多个键映射到指定值，则返回&nbsp;<code>true</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableSet.html" rel="nofollow">NavigableSet</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#descendingKeySet--" rel="nofollow">descendingKeySet</a>()</code> 返回此地图中包含的键的相反顺序<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableSet.html" rel="nofollow"><code>NavigableSet</code></a>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableMap.html" rel="nofollow">NavigableMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#descendingMap--" rel="nofollow">descendingMap</a>()</code> 返回此映射中包含的映射的反向排序视图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow">Set</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#entrySet--" rel="nofollow">entrySet</a>()</code> 返回此地图中包含的映射的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow"><code>Set</code></a>视图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#firstEntry--" rel="nofollow">firstEntry</a>()</code> 返回与该地图中的最小键相关联的键值映射，如果地图为空，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#firstKey--" rel="nofollow">firstKey</a>()</code> 返回此地图中当前的第一个（最低）键。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#floorEntry-K-" rel="nofollow">floorEntry</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回与小于或等于给定键的最大键相关联的键值映射，如果没有此键，则&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#floorKey-K-" rel="nofollow">floorKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回小于或等于给定键的最大键，如果没有这样的键，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#forEach-java.util.function.BiConsumer-" rel="nofollow">forEach</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiConsumer.html" rel="nofollow">BiConsumer</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;&nbsp;action)</code> 对此映射中的每个条目执行给定的操作，直到所有条目都被处理或操作引发异常。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#get-java.lang.Object-" rel="nofollow">get</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 返回到指定键所映射的值，或&nbsp;<code>null</code>如果此映射包含该键的映射。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/SortedMap.html" rel="nofollow">SortedMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#headMap-K-" rel="nofollow">headMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;toKey)</code> 返回此地图部分的视图，其密钥严格小于&nbsp;<code>toKey</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableMap.html" rel="nofollow">NavigableMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#headMap-K-boolean-" rel="nofollow">headMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;toKey, boolean&nbsp;inclusive)</code> 返回此地图部分的视图，其键值小于（或等于，如果&nbsp;<code>inclusive</code>为真）&nbsp;<code>toKey</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#higherEntry-K-" rel="nofollow">higherEntry</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回与最小密钥相关联的密钥值映射严格大于给定密钥，如果没有这样的密钥则&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#higherKey-K-" rel="nofollow">higherKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回严格大于给定键的最小键，如果没有这样的键，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow">Set</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#keySet--" rel="nofollow">keySet</a>()</code> 返回此地图中包含的键的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow"><code>Set</code></a>视图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#lastEntry--" rel="nofollow">lastEntry</a>()</code> 返回与该地图中最大关键字关联的键值映射，如果地图为空，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#lastKey--" rel="nofollow">lastKey</a>()</code> 返回当前在此地图中的最后（最高）键。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#lowerEntry-K-" rel="nofollow">lowerEntry</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回与最大密钥相关联的密钥值映射严格小于给定密钥，如果没有这样的密钥，则&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#lowerKey-K-" rel="nofollow">lowerKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key)</code> 返回严格小于给定键的最大键，如果没有这样的键，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableSet.html" rel="nofollow">NavigableSet</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#navigableKeySet--" rel="nofollow">navigableKeySet</a>()</code> 返回此地图中包含的键的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableSet.html" rel="nofollow"><code>NavigableSet</code></a>视图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#pollFirstEntry--" rel="nofollow">pollFirstEntry</a>()</code> 删除并返回与该地图中的最小键相关联的键值映射，如果地图为空，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#pollLastEntry--" rel="nofollow">pollLastEntry</a>()</code> 删除并返回与该地图中最大密钥相关联的键值映射，如果地图为空，则返回&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#put-K-V-" rel="nofollow">put</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&nbsp;value)</code> 将指定的值与此映射中的指定键相关联。 </td> 
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 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#putAll-java.util.Map-" rel="nofollow">putAll</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.html" rel="nofollow">Map</a>&lt;? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;&nbsp;map)</code> 将指定地图的所有映射复制到此地图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#remove-java.lang.Object-" rel="nofollow">remove</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 从此TreeMap中删除此键的映射（如果存在）。 </td> 
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 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#replace-K-V-" rel="nofollow">replace</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&nbsp;value)</code> 只有当目标映射到某个值时，才能替换指定键的条目。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#replace-K-V-V-" rel="nofollow">replace</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&nbsp;oldValue,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&nbsp;newValue)</code> 仅当当前映射到指定的值时，才能替换指定键的条目。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#replaceAll-java.util.function.BiFunction-" rel="nofollow">replaceAll</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiFunction.html" rel="nofollow">BiFunction</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;&nbsp;function)</code> 将每个条目的值替换为对该条目调用给定函数的结果，直到所有条目都被处理或该函数抛出异常。 </td> 
 </tr> 
 <tr> 
 <td><code>int</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#size--" rel="nofollow">size</a>()</code> 返回此地图中键值映射的数量。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableMap.html" rel="nofollow">NavigableMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#subMap-K-boolean-K-boolean-" rel="nofollow">subMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;fromKey, boolean&nbsp;fromInclusive,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;toKey, boolean&nbsp;toInclusive)</code> 返回此地图部分的视图，其关键范围为&nbsp;<code>fromKey</code>至&nbsp;<code>toKey</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/SortedMap.html" rel="nofollow">SortedMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#subMap-K-K-" rel="nofollow">subMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;fromKey,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;toKey)</code> 返回此地图部分的视图，其关键字范围从&nbsp;<code>fromKey</code>&nbsp;（含）到&nbsp;<code>toKey</code>&nbsp;，独占。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/SortedMap.html" rel="nofollow">SortedMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#tailMap-K-" rel="nofollow">tailMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;fromKey)</code> 返回此地图部分的视图，其键大于等于&nbsp;<code>fromKey</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/NavigableMap.html" rel="nofollow">NavigableMap</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#tailMap-K-boolean-" rel="nofollow">tailMap</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">K</a>&nbsp;fromKey, boolean&nbsp;inclusive)</code> 返回此地图部分的视图，其键大于（或等于，如果&nbsp;<code>inclusive</code>为真）&nbsp;<code>fromKey</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Collection.html" rel="nofollow">Collection</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/TreeMap.html#values--" rel="nofollow">values</a>()</code> 返回此地图中包含的值的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Collection.html" rel="nofollow"><code>Collection</code></a>视图。 </td> 
 </tr> 
 </tbody> 
</table>

# HashMap #

<table> 
 <tbody> 
 <tr> 
 <th>Modifier and Type</th> 
 <th>Method and Description</th> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#clear--" rel="nofollow">clear</a>()</code> 从这张地图中删除所有的映射。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#clone--" rel="nofollow">clone</a>()</code> 返回此&nbsp;HashMap实例的浅拷贝：键和值本身不被克隆。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#compute-K-java.util.function.BiFunction-" rel="nofollow">compute</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiFunction.html" rel="nofollow">BiFunction</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;remappingFunction)</code> 尝试计算用于指定键和其当前映射的值的映射（或&nbsp;<code>null</code>如果没有当前映射）。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#computeIfAbsent-K-java.util.function.Function-" rel="nofollow">computeIfAbsent</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/Function.html" rel="nofollow">Function</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;mappingFunction)</code> 如果指定的键尚未与值相关联（或映射到&nbsp;<code>null</code>&nbsp;），则尝试使用给定的映射函数计算其值，并将其输入到此映射中，除非&nbsp;<code>null</code>&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#computeIfPresent-K-java.util.function.BiFunction-" rel="nofollow">computeIfPresent</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiFunction.html" rel="nofollow">BiFunction</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;remappingFunction)</code> 如果指定的密钥的值存在且非空，则尝试计算给定密钥及其当前映射值的新映射。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#containsKey-java.lang.Object-" rel="nofollow">containsKey</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 如果此映射包含指定键的映射，则返回&nbsp;true&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#containsValue-java.lang.Object-" rel="nofollow">containsValue</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;value)</code> 如果此地图将一个或多个键映射到指定值，则返回&nbsp;true&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow">Set</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.Entry.html" rel="nofollow">Map.Entry</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#entrySet--" rel="nofollow">entrySet</a>()</code> 返回此地图中包含的映射的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow"><code>Set</code></a>视图。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#forEach-java.util.function.BiConsumer-" rel="nofollow">forEach</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiConsumer.html" rel="nofollow">BiConsumer</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;action)</code> 对此映射中的每个条目执行给定的操作，直到所有条目都被处理或操作引发异常。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#get-java.lang.Object-" rel="nofollow">get</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 返回到指定键所映射的值，或&nbsp;<code>null</code>如果此映射包含该键的映射。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#getOrDefault-java.lang.Object-V-" rel="nofollow">getOrDefault</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;defaultValue)</code> 返回到指定键所映射的值，或&nbsp;<code>defaultValue</code>如果此映射包含该键的映射。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#isEmpty--" rel="nofollow">isEmpty</a>()</code> 如果此地图不包含键值映射，则返回&nbsp;true&nbsp;。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow">Set</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#keySet--" rel="nofollow">keySet</a>()</code> 返回此地图中包含的键的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Set.html" rel="nofollow"><code>Set</code></a>视图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#merge-K-V-java.util.function.BiFunction-" rel="nofollow">merge</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;value,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiFunction.html" rel="nofollow">BiFunction</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;remappingFunction)</code> 如果指定的键尚未与值相关联或与null相关联，则将其与给定的非空值相关联。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#put-K-V-" rel="nofollow">put</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;value)</code> 将指定的值与此映射中的指定键相关联。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#putAll-java.util.Map-" rel="nofollow">putAll</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Map.html" rel="nofollow">Map</a>&lt;? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;m)</code> 将指定地图的所有映射复制到此地图。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#putIfAbsent-K-V-" rel="nofollow">putIfAbsent</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;value)</code> 如果指定的键尚未与某个值相关联（或映射到&nbsp;<code>null</code>&nbsp;），则将其与给定值相关联并返回&nbsp;<code>null</code>&nbsp;，否则返回当前值。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#remove-java.lang.Object-" rel="nofollow">remove</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key)</code> 从该地图中删除指定键的映射（如果存在）。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#remove-java.lang.Object-java.lang.Object-" rel="nofollow">remove</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/lang/Object.html" rel="nofollow">Object</a>&nbsp;value)</code> 仅当指定的密钥当前映射到指定的值时删除该条目。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a></code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#replace-K-V-" rel="nofollow">replace</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;value)</code> 只有当目标映射到某个值时，才能替换指定键的条目。 </td> 
 </tr> 
 <tr> 
 <td><code>boolean</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#replace-K-V-V-" rel="nofollow">replace</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>&nbsp;key,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;oldValue,&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&nbsp;newValue)</code> 仅当当前映射到指定的值时，才能替换指定键的条目。 </td> 
 </tr> 
 <tr> 
 <td><code>void</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#replaceAll-java.util.function.BiFunction-" rel="nofollow">replaceAll</a>(<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/function/BiFunction.html" rel="nofollow">BiFunction</a>&lt;? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">K</a>,? super&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>,? extends&nbsp;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;&nbsp;function)</code> 将每个条目的值替换为对该条目调用给定函数的结果，直到所有条目都被处理或该函数抛出异常。 </td> 
 </tr> 
 <tr> 
 <td><code>int</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#size--" rel="nofollow">size</a>()</code> 返回此地图中键值映射的数量。 </td> 
 </tr> 
 <tr> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Collection.html" rel="nofollow">Collection</a>&lt;<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html" rel="nofollow">V</a>&gt;</code></td> 
 <td><code><a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/HashMap.html#values--" rel="nofollow">values</a>()</code> 返回此地图中包含的值的<a href="http://www.matools.com/file/manual/jdk_api_1.8_google/java/util/Collection.html" rel="nofollow"><code>Collection</code></a>视图。 </td> 
 </tr> 
 </tbody> 
</table>

# LinkedHashMap #

# 部分示例代码  #

import java.util.*;
 import java.util.stream.Collectors;
 
 public class MyMap {
 public static void main(String[] args) {
 MyMap myMap = new MyMap();
 myMap.TestTreeMap();
 }
 
 
 /**
 *HashMap 与TreeMap操作类似，HashMap无序，TreeMap有序。LinkedHashMap继承与HashMap，它有序。
 */
 
 /**
 * 自带排序
 */
 public void TestTreeMap(){
 Map<String, String> mytreeMap = new TreeMap<String, String>(){
 {
 put("zz", "333");
 put("cc", "11111");
 put("aa", "999");
 put("xx", "777");
 put("b", "888");
 put("3z", "666");
 }};
 
 System.out.println("map集合为："+mytreeMap);
 
 /**
 * 遍历容器
 */
 //方式一：
 System.out.println("使用entrySet().iterator()：");
 Iterator iter1 = mytreeMap.entrySet().iterator();
 while (iter1.hasNext()){
 Map.Entry<String, String> entry = (Map.Entry<String,String>)iter1.next();
 System.out.println("key: "+ entry.getKey() + " value: "+ entry.getValue());
 }
 //方式二：
 System.out.println("使用keySet().iterator()");
 Iterator iter2 = mytreeMap.keySet().iterator();
 while (iter2.hasNext()){
 String str1 = (String)iter2.next();
 System.out.println("key: " + str1);
 }
 //方式三:
 System.out.println("使用foreach()方法遍历");
 mytreeMap.forEach((key,val)-> System.out.println("key: "+ key + " value: "+ val));
 //方式四：
 System.out.println("使用for遍历：");
 for (Map.Entry<String, String> tmp : mytreeMap.entrySet()){
 System.out.println("key: "+ tmp.getKey() + " value: "+ tmp.getValue());
 }
 
 /**
 * 判断键值是否存在
 */
 if (mytreeMap.containsKey("zz")){
 System.out.println("map中有key = zz的键值对");
 }
 if (mytreeMap.containsValue("3333")){
 System.out.println("map中有value = 3333的键值对");
 }
 
 /**
 * 按键排序
 */
 System.out.println(mytreeMap);
 Map<String,String> sortMap = mytreeMap.entrySet().stream()
 .sorted(Map.Entry.comparingByKey())
 .collect(Collectors.toMap(Map.Entry::getKey,
 Map.Entry::getValue,
 (oldval,newval)-> oldval,
 LinkedHashMap::new)); //注意这里必须是LinkedHashMap，其他的不行
 System.out.println("按键排序："+sortMap);
 //
 /**
 * 按值排序,如果要是想反序，在比较key或者value时操作：Map.Entry.<String, String>comparingByValue().reversed()
 */
 Map<String,String> sortMap2 = mytreeMap.entrySet().stream()
 .sorted(Map.Entry.comparingByValue())
 .collect(Collectors.toMap(Map.Entry::getKey,
 Map.Entry::getValue,
 (oldval,newval)-> oldval,
 LinkedHashMap::new)); //注意这里必须是LinkedHashMap，其他的不行
 System.out.println("按值排序："+sortMap2);
 
 //排序结果
 // {zz=333, cc=11111, aa=999, xx=777, b=888, 3z=666}
 // 按键排序：{3z=666, aa=999, b=888, cc=11111, xx=777, zz=333}
 // 按值排序：{cc=11111, zz=333, 3z=666, xx=777, b=888, aa=999}
 }
 }

# 排序 #

这里针对排序重点记录一下

### Map集合 ###

Map<String, String> map = new HashMap<String, String>();
 map.put("c", "222");
 map.put("a", "333");
 map.put("b", "44");
 map.put("d", "111");
 
 System.out.println(map);

### 传统方法排序 ###

/**
 * 使用Collections.sort方法排序，先将entrySet转换为list，再排序
 */
 List<Map.Entry<String,String>> list = new ArrayList<Map.Entry<String,String>>(map.entrySet());
 Collections.sort(list,new Comparator<Map.Entry<String,String>>() {
 //升序排序，如果降序换一下o1与o2位置
 public int compare(Map.Entry<String, String> o1,
 Map.Entry<String, String> o2) {
 return o2.getValue().compareTo(o1.getValue()); //按值排序
 // return o1.getKey().compareTo(o2.getKey()); //按键排序
 }
 
 });
 System.out.println("按值排序："+ list);

如果是自定义类，可以直接实现 Comparable接口的 compareTo方法即可。

### Lambda方法排序 ###

LinkedList<Map.Entry<String,String>> list2 = new LinkedList<>(map.entrySet());
 Collections.sort(list2, Comparator.comparing(Map.Entry<String,String>::getKey, Comparator.naturalOrder()));
 System.out.println("按键升排序："+ list2);
 
 Collections.sort(list2, Comparator.comparing(Map.Entry<String,String>::getKey, Comparator.reverseOrder()));
 System.out.println("按键降排序："+ list);
 
 // {a=333, b=44, c=222, d=111}
 // 按值排序：[b=44, a=333, c=222, d=111]
 // 按键升排序：[a=333, b=44, c=222, d=111]
 // 按键降排序：[b=44, a=333, c=222, d=111]

如果想按值排序，只需要将getKey换成getValue即可。

### 使用stream排序 ###

Map<String, String> mytreeMap = new HashMap<String, String>(){
 {
 	put("zz", "333");
 	put("cc", "11111");
 	put("aa", "999");
 	put("xx", "777");
 	put("b", "888");
 	put("3z", "666");
 }};
 
 /**
 * 按键排序
 */
 System.out.println(mytreeMap);
 Map<String,String> sortMap = mytreeMap.entrySet().stream()
 		.sorted(Map.Entry.comparingByKey())
 		.collect(Collectors.toMap(Map.Entry::getKey,
 				Map.Entry::getValue,
 				(oldval,newval)-> oldval,
 				LinkedHashMap::new)); //注意这里必须是LinkedHashMap，其他的不行
 System.out.println("按键排序："+sortMap);
 
 /**
 * 按值排序,如果要是想反序，在比较key或者value时操作：Map.Entry.<String, String>comparingByValue().reversed()
 */
 Map<String,String> sortMap2 = mytreeMap.entrySet().stream()
 		.sorted(Map.Entry.comparingByValue())
 		.collect(Collectors.toMap(Map.Entry::getKey,
 				Map.Entry::getValue,
 				(oldval,newval)-> oldval,
 				LinkedHashMap::new)); //注意这里必须是LinkedHashMap，其他的不行
 System.out.println("按值排序："+sortMap2);