Java EnumMap get() 方法

java.util.EnumMap.get() 方法返回指定键映射到的值，如果是则返回 null该映射不包含该键的映射。

返回值 null 并不一定表示该映射不包含该键的映射；映射也可能显式地将键映射为 null。

语法

public V get(Object key)

这里，V是容器维护的值的类型。

参数

返回值

返回指定键映射到的值，如果此映射不包含该键的映射，则返回 null。

异常

示例:

在下面的示例中，java.util.EnumMap.get() 方法返回给定键中映射到的值枚举映射。

import java.util.*;

public class MyClass {
  
  //创建一个枚举
  public enum weekday{
    MON, TUE, WED, THU, FRI
  }

  public static void main(String[] args) {
    //创建EnumMap
    EnumMap<weekday,Integer> MyMap = 
        new EnumMap<weekday,Integer>(weekday.class);

    //关联MyMap中的值
    MyMap.put(weekday.MON, 1);
    MyMap.put(weekday.TUE, 2);
    MyMap.put(weekday.WED, 3);
    MyMap.put(weekday.THU, 4);
    MyMap.put(weekday.FRI, 5);

    //打印指定键的映射值
    System.out.println("MON is mapped to: " + MyMap.get(weekday.MON));
    System.out.println("WED is mapped to: " + MyMap.get(weekday.WED));
    System.out.println("FRI is mapped to: " + MyMap.get(weekday.FRI)); 
  }
}

上述代码的输出将是:

MON is mapped to: 1
WED is mapped to: 3
FRI is mapped to: 5