Java EnumMap clear() 方法

java.util.EnumMap.clear() 方法用于从此映射中删除所有映射。

语法

public void clear()

参数

无需参数。

返回值

void 类型.

异常

示例:

在下面的示例中，java.util .EnumMap.clear()方法用于清除给定map的所有映射。

import java.util.*;

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

  public static void main(String[] args) {
    //创建一个EnumMap
    EnumMap<weekday,Integer> MyMap = 
        new EnumMap<weekday,Integer>(weekday.class);

    //关联map中的值
    MyMap.put(weekday.SUN, 0);
    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);
    MyMap.put(weekday.SAT, 6);

    //打印EnumMap
    System.out.println("Before applying clear() method.");
    System.out.println("MyMap contains: " + MyMap);

    //使用clear方法清除EnumMap的内容
    MyMap.clear();

    //打印EnumMap
    System.out.println("\nAfter applying clear() method."); 
    System.out.println("MyMap contains: " + MyMap);   
  }
}

上述代码的输出将是:

Before applying clear() method.
MyMap contains: {SUN=0, MON=1, TUE=2, WED=3, THU=4, FRI=5, SAT=6}

After applying clear() method.
MyMap contains: {}