Java IdentityHashMap entrySet()用法及代码示例

Java中的java.util.IdentityHashMap.entrySet()方法用于根据Map中包含的相同元素创建集合。它本质上返回了身份哈希映射的集合视图，或者我们可以创建一个新集合并将映射元素存储到其中。

用法:

Identity_HashMap.entrySet()

参数：该方法不带任何参数。

返回值：该方法返回与Map具有相同元素的集合。

以下示例程序旨在说明java.util.IdentityHashMap.entrySet()方法：
示例1:将字符串值映射到整数键。

// Java code to illustrate the entrySet() method 
import java.util.*; 
  
public class Identity_Hash_Map_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty IdentityHashMap 
        IdentityHashMap<Integer, String> identity_hash =  
                      new IdentityHashMap<Integer, String>(); 
  
        // Mapping string values to int keys 
        identity_hash.put(10, "Geeks"); 
        identity_hash.put(15, "4"); 
        identity_hash.put(20, "Geeks"); 
        identity_hash.put(25, "Welcomes"); 
        identity_hash.put(30, "You"); 
  
        // Displaying the IdentityHashMap 
        System.out.println("Initial Mappings are: " +  
                                             identity_hash); 
  
        // Using entrySet() to get the set view 
        System.out.println("The set is: " +  
                                   identity_hash.entrySet()); 
    } 
}

输出：

Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The set is: [10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4]

示例2:将整数值映射到字符串键。

// Java code to illustrate the entrySet() method 
import java.util.*; 
  
public class Identity_Hash_Map_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty IdentityHashMap 
        IdentityHashMap<String, Integer> identity_hash =  
                       new IdentityHashMap<String, Integer>(); 
  
        // Mapping int values to string keys 
        identity_hash.put("Geeks", 10); 
        identity_hash.put("4", 15); 
        identity_hash.put("Geeks", 20); 
        identity_hash.put("Welcomes", 25); 
        identity_hash.put("You", 30); 
  
        // Displaying the IdentityHashMap 
        System.out.println("Initial Mappings are: " +  
                                               identity_hash); 
  
        // Using entrySet() to get the set view 
        System.out.println("The set is: " +  
                                   identity_hash.entrySet()); 
    } 
}

输出：

Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The set is: [Geeks=20, Welcomes=25, You=30, 4=15]

注意：可以对具有不同数据类型的变化和组合的任何类型的映射执行相同的操作。

相关用法

注：本文由纯净天空筛选整理自Chinmoy Lenka大神的英文原创作品 IdentityHashMap entrySet() Method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。