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  • 2018-08-07  21:19:48        
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    Java.util.IdentityHashMap.clone()

    java.util.IdentityHashMap.clone() 方法用于返回所提到的哈希映射的副本。它只是创建了map的副本。

    句法:

    Identity_HashMap.clone()

    参数:该方法不接受任何参数。

    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() 的工作方法

    程序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}

    程序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}

     
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