Java中的 EnumMap putAll(map) 方法

Java中的Java .util.EnumMap.putAll( map ) 方法用于将所有映射从一个映射复制到一个较新的映射。较旧的映射被替换为较新的映射。

句法：

void putAll(map)

参数：该方法采用一个参数映射。这是要复制到较新的地图。

返回值该方法不返回任何值。

下面的程序说明了 putAll() 方法：

方案一：

// Java program to demonstrate keySet()
import java.util.*;
  
// An enum of geeksforgeeks
public enum gfg {
    Global_today,
    India_today,
    China_today
};
  
class Enum_demo {
    public static void main(String[] args)
    {
  
        EnumMap mp1 = 
                     new EnumMap(gfg.class);
  
        EnumMap mp2 = 
                     new EnumMap(gfg.class);
  
        // Values are associated
        mp1.put(gfg.Global_today, 799);
        mp1.put(gfg.India_today, 69);
  
        // Copies all the mappings of mp1 to mp2
        mp2.putAll(mp1);
  
        // Prints the first map
        System.out.println("Mappings in Map1: " + mp1);
  
        // Prints the second map
        System.out.println("Mappings in Map2: " + mp2);
    }
}

输出：

Mappings in Map1: {Global_today=799, India_today=69}
Mappings in Map2: {Global_today=799, India_today=69}

方案二：

// Java program to demonstrate the working of keySet()
import java.util.*;
  
// an enum of geeksforgeeks
// visitors in India and United States
public enum gfg {
  
    India_today,
    United_States_today
}
;
  
class Enum_demo {
    public static void main(String[] args)
    {
  
        EnumMap mp1 = 
                     new EnumMap(gfg.class);
  
        EnumMap mp2 = 
                     new EnumMap(gfg.class);
  
        // Values are associated
        mp1.put(gfg.India_today, "61.8%");
        mp1.put(gfg.United_States_today, "18.2%");
  
        // Copies all the mappings of mp1 to mp2
        mp2.putAll(mp1);
  
        // Prints the first map
        System.out.println("Mappings in Map1: " + mp1);
  
        // Prints the second map
        System.out.println("Mappings in Map2: " + mp2);
    }
}

输出：

Mappings in Map1: {India_today=61.8%, United_States_today=18.2%}
Mappings in Map2: {India_today=61.8%, United_States_today=18.2%}