Java IdentityHashMap clone()用法及代碼示例

java.util.IdentityHashMap.clone()方法用於返回所提及哈希表的淺拷貝。它隻是創建Map的副本。

用法:

Identity_HashMap.clone()

參數：該方法不帶任何參數。

返回值：該方法僅返回哈希圖的副本。

以下程序用於說明java.util.IdentityHashMap.clone()方法的用法：
示例1:

// Java code to illustrate the clone() 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); 
  
        // Displaying the cloned Map using clone() 
        System.out.println("The cloned map: " +  
                                    identity_hash.clone()); 
    } 
}

輸出：

Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The cloned map: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}

示例2:

// Java code to illustrate the clone() method 
import java.util.*; 
  
public class Identity_Hash_Map_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty hash map 
        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); 
  
        // Displaying the cloned map using clone() 
        System.out.println("The cloned map: " +  
                                 identity_hash.clone()); 
    } 
}

輸出：

Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The cloned map: {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 clone() 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。