Java中的字段 isEnumConstant() 方法及示例

Java.lang.reflect.Field的isEnumConstant()方法用于检查该字段是否代表枚举类型的元素。如果此字段表示枚举类型的元素，则方法返回 true，否则返回 false。

句法：

public boolean isEnumConstant()

参数：此方法不接受任何内容。

Return ：当且仅当此字段表示枚举类型的元素时，此方法才返回true 。

下面的程序说明了 isEnumConstant() 方法：
方案一：

// Java program to illustrate
// isEnumConstant () method
  
import java.lang.reflect.Field;
import java.time.Month;
  
public class GFG {
  
    public static void main(String[] args)
        throws NoSuchFieldException
    {
  
        // get all declared fields of Month class
        Field[] declaredFields
            = Month.class.getDeclaredFields();
  
        // loop through Field array
        // and print Field name and
        // check whether the field is EnumConstant
        for (int i = 0; i < declaredFields.length; i++) {
            System.out.print(
                "Field --> Name: "
                + declaredFields[i].getName()
                + "; isEnumConstant: "
                + declaredFields[i]
                      .isEnumConstant()
                + "\n");
        }
    }
}

输出：

Field --> Name: JANUARY; isEnumConstant: true
Field --> Name: FEBRUARY; isEnumConstant: true
Field --> Name: MARCH; isEnumConstant: true
Field --> Name: APRIL; isEnumConstant: true
Field --> Name: MAY; isEnumConstant: true
Field --> Name: JUNE; isEnumConstant: true
Field --> Name: JULY; isEnumConstant: true
Field --> Name: AUGUST; isEnumConstant: true
Field --> Name: SEPTEMBER; isEnumConstant: true
Field --> Name: OCTOBER; isEnumConstant: true
Field --> Name: NOVEMBER; isEnumConstant: true
Field --> Name: DECEMBER; isEnumConstant: true
Field --> Name: ENUMS; isEnumConstant: false
Field --> Name: $VALUES; isEnumConstant: false

方案二：

// Java program to illustrate
// isEnumConstant () method
  
import java.lang.reflect.Field;
  
public class GFG {
  
    public static void main(String[] args)
        throws NoSuchFieldException
    {
  
        // get all declared fields of Symbols class
        Field[] declaredFields
            = Symbols.class.getDeclaredFields();
  
        // loop through Field array
        // and print Field name and
        // check whether the field is EnumConstant
        for (int i = 0; i < declaredFields.length; i++) {
            System.out.print(
                "Field --> Name: "
                + declaredFields[i].getName()
                + "; isEnumConstant: "
                + declaredFields[i]
                      .isEnumConstant()
                + "\n");
        }
    }
  
    private static enum Symbols {
        Alpha,
        Beta,
        Gamma
    }
}

输出：

Field --> Name: Alpha; isEnumConstant: true
Field --> Name: Beta; isEnumConstant: true
Field --> Name: Gamma; isEnumConstant: true
Field --> Name: ENUM$VALUES; isEnumConstant: false

参考资料： https: Java/lang/reflect/Field.html#isEnumConstant–