Java IdentityHashMap clone()用法及代码示例

java.util.IdentityHashMap.clone()方法用于返回所提及哈希表的浅拷贝。它只是创建Map的副本。

用法:

Identity_HashMap.clone()

参数：该方法不带任何参数。

返回值：该方法仅返回哈希图的副本。

以下程序用于说明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()); 
    } 
}

输出：

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()); 
    } 
}

输出：

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 clone() 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。