Java中的IdentityHashMap clone()方法

Java.util.IdentityHashMap.clone() 方法用于返回上述哈希映射的浅表副本。它只是创建地图的副本。

句法：

Identity_HashMap.clone()

参数：该方法不带任何参数。

返回值：该方法只返回哈希映射的副本。

下面的程序用于说明Java.util.IdentityHashMap.clone() 方法的工作：
方案一：

// 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 identity_hash = 
                      new IdentityHashMap();
  
        // 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}

方案二：

// 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 identity_hash = 
                  new IdentityHashMap();
  
        // 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：可以对任何类型的映射执行相同的操作，这些映射具有不同数据类型的变化和组合。