Java IdentityHashMap entrySet()用法及代碼示例

Java中的java.util.IdentityHashMap.entrySet()方法用於根據Map中包含的相同元素創建集合。它本質上返回了身份哈希映射的集合視圖，或者我們可以創建一個新集合並將映射元素存儲到其中。

用法:

Identity_HashMap.entrySet()

參數：該方法不帶任何參數。

返回值：該方法返回與Map具有相同元素的集合。

以下示例程序旨在說明java.util.IdentityHashMap.entrySet()方法：
示例1:將字符串值映射到整數鍵。

// 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()); 
    } 
}

輸出：

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:將整數值映射到字符串鍵。

// 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()); 
    } 
}

輸出：

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

注意：可以對具有不同數據類型的變化和組合的任何類型的映射執行相同的操作。

相關用法

注：本文由純淨天空篩選整理自Chinmoy Lenka大神的英文原創作品 IdentityHashMap entrySet() Method in Java。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。