Java 简明教程
Java LinkedHashMap Class
Introduction
Java LinkedHashMap 类是 Map 接口的散列表和链表实现，具有可预测的迭代顺序。关于 LinkedHashMap 的重点如下：
The Java LinkedHashMap class is Hash table and Linked list implementation of the Map interface, with predictable iteration order. Following are the important points about LinkedHashMap −
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The class provides all of the optional Map operations, and permits null elements.
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The Iteration over a HashMap is likely to be more expensive.
Class declaration
以下是 java.util.LinkedHashMap 类的声明：
Following is the declaration for java.util.LinkedHashMap class −
public class LinkedHashMap<K,V>
extends HashMap<K,V>
implements Map<K,V>Parameters
以下是 java.util.LinkedHashMap 类的参数：
Following is the parameter for java.util.LinkedHashMap class −
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K − This is the type of keys maintained by this map.
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V − This is the the type of mapped values.
Methods inherited
此类从以下类中继承方法：
This class inherits methods from the following classes −
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java.util.HashMap
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java.util.AbstarctMap
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java.util.Object
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java.util.Map
Getting a Value from LinkedHashMap Example
以下示例显示 Java LinkedHashMap get() 方法用于从映射中基于键获取值的用法。我们创建了一个 Integer、Integer 的映射对象。然后添加一些条目，并打印映射。使用 get() 方法，检索并打印一个值。
The following example shows the usage of Java LinkedHashMap get() method to get a value based on a key from a Map. We’ve created a Map object of Integer,Integer. Then few entries are added, map is printed. Using get() method, a value is retrieved and printed.
package com.tutorialspoint;
import java.util.LinkedHashMap;
public class LinkedHashMapDemo {
public static void main(String args[]) {
// create hash map
LinkedHashMap<Integer,Integer> newmap = new LinkedHashMap<>();
// populate hash map
newmap.put(1, 1);
newmap.put(2, 2);
newmap.put(3, 3);
System.out.println("Initial map elements: " + newmap);
System.out.println("Value: " + newmap.get(1));
}
}