Java中的 EnumMap clone() 方法

Java中的Java .util.EnumMap.clone() 方法用于将一个映射的映射值复制到另一个映射。它基本上创建了这张地图的浅表副本。

句法：

Enum_map_2 = Enum_map_1.clone()

参数：该方法不接受任何参数。

返回值：该方法返回一个 EnumMap 的浅拷贝。

下面的程序说明了Java.util.EnumMap.clone() 方法

方案一：

// Java program to demonstrate clone() method
import java.util.*;
  
// An enum of fruits price is created
public enum Price_of_Fruits {
    Orange,
    Apple,
    Banana,
    Pomegranate,
    Guava
};
  
class Enum_map {
    public static void main(String[] args)
    {
  
        EnumMap mp1 = new EnumMap(Price_of_Fruits.class);
  
        EnumMap mp2 = new EnumMap(Price_of_Fruits.class);
  
        // Values are associated in mp1
        mp1.put(Price_of_Fruits.Orange, 30);
        mp1.put(Price_of_Fruits.Apple, 60);
        mp1.put(Price_of_Fruits.Banana, 40);
        mp1.put(Price_of_Fruits.Pomegranate, 120);
        mp1.put(Price_of_Fruits.Guava, 20);
  
        // Price of fruits in mp1
        System.out.println("Price of fruits in 1st map " + mp1);
  
        // Copying the values of mp1 to mp2
        mp2 = mp1.clone();
  
        // Price of fruits in mp2
        System.out.println("Price of fruits in 2nd map " + mp2);
    }
}

输出：

Price of fruits in 1st map {Orange=30, Apple=60, Banana=40, Pomegranate=120, Guava=20}
Price of fruits in 2nd map {Orange=30, Apple=60, Banana=40, Pomegranate=120, Guava=20}

方案二：

// Java program to demonstrate clone() method
import java.util.*;
  
// An enum of gfg ranking is created
public enum gfg_ranking {
    Global_2018,
    India_2018
};
  
class Enum_map {
    public static void main(String[] args)
    {
  
        EnumMap mp1 = new EnumMap(gfg_ranking.class);
  
        EnumMap mp2 = new EnumMap(gfg_ranking.class);
  
        // Values are associated in mp1
        mp1.put(gfg_ranking.Global_2018, 800);
        mp1.put(gfg_ranking.India_2018, 72);
  
        // Price of fruits in mp1
        System.out.println("GeeksforGeeks ranking in first map " + mp1);
  
        // Copying the values of mp1 to mp2
        mp2 = mp1.clone();
  
        // Price of fruits in mp2
        System.out.println("GeeksforGeeks ranking in second map " + mp2);
    }
}

输出：

GeeksforGeeks ranking in first map {Global_2018=800, India_2018=72}
GeeksforGeeks ranking in second map {Global_2018=800, India_2018=72}