Java EnumMap entrySet()用法及代码示例

Java中的Java.util.EnumMap.entrySet()方法用于创建EnumMap中包含的元素的集合。它本质上返回枚举映射的设置视图。

用法:

enum_map.entrySet()

参数：该方法不带任何参数。

返回值：该方法返回此enum_map中包含的映射的设置视图。

以下示例程序旨在说明entrySet()方法：

示例1:

// Java program to demonsrate entrySet() method 
import java.util.*; 
  
// An enum of gfg rank is created 
public enum rank_countries { 
    India, 
    United_States, 
    China, 
    Japan, 
    Canada, 
    Russia 
} 
; 
  
class Enum_map { 
    public static void main(String[] args) 
    { 
  
        EnumMap<rank_countries, Integer> mp = new 
        EnumMap<rank_countries, Integer>(rank_countries.class); 
  
        // Values are associated in mp 
        mp.put(rank_countries.India, 72); 
        mp.put(rank_countries.United_States, 1083); 
        mp.put(rank_countries.China, 4632); 
        mp.put(rank_countries.Japan, 6797); 
  
        // Map view 
        System.out.println("Map view: " + mp); 
  
        // Creating a new set of the mappings 
        // contained in map 
        Set<Map.Entry<rank_countries, Integer> > set_view =  
                                                mp.entrySet(); 
  
        // Set view of the mappings 
        System.out.println("Set view of the map: " + set_view); 
    } 
}

输出：

Map view: {India=72, United_States=1083, China=4632, Japan=6797}
Set view of the map: [India=72, United_States=1083, China=4632, Japan=6797]

示例2:

// Java program to demonsrate entrySet() method 
import java.util.*; 
  
// An enum of gfg ranking worldwide and in india 
public enum gfg { 
    Global_2018, 
    India_2018 
}; 
  
class Enum_map { 
    public static void main(String[] args) 
    { 
  
        EnumMap<gfg, Integer> mp = new 
              EnumMap<gfg, Integer>(gfg.class); 
  
        // Values are associated in mp 
        mp.put(gfg.Global_2018, 800); 
        mp.put(gfg.India_2018, 72); 
  
        // Mapping view 
        System.out.println("Mapping view: " + mp); 
  
        // Creating a new set of the mappings  
        Set<Map.Entry<gfg, Integer> > set_view =  
                                    mp.entrySet(); 
  
        // Set view of the mappings 
        System.out.println("Set view of the map: "
                                      + set_view); 
    } 
}

输出：

Mapping view: {Global_2018=800, India_2018=72}
Set view of the map: [Global_2018=800, India_2018=72]

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注：本文由纯净天空筛选整理自akash1295大神的英文原创作品 EnumMap entrySet() Method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。