Java EnumMap putAll(map)方法

Java.util.EnumMap.putAll( map )方法用于将一个Map中的所有映射复制到一个较新的Map中。旧的映射被替换到新的映射中。

语法

void putAll(map)

参数： 该方法需要一个参数map。它是要被复制到较新的Map。

返回值 该方法不返回任何值。

下面的程序说明了putAll()方法。

程序1:

// 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<gfg, Integer> mp1 = 
                     new EnumMap<gfg, Integer>(gfg.class);
  
        EnumMap<gfg, Integer> mp2 = 
                     new EnumMap<gfg, Integer>(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}

程序2

// 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<gfg, String> mp1 = 
                     new EnumMap<gfg, String>(gfg.class);
  
        EnumMap<gfg, String> mp2 = 
                     new EnumMap<gfg, String>(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%}