Java Field isEnumConstant()方法及示例

java.lang.reflect.Field 的 isEnumConstant() 方法用于检查这个字段是否代表一个枚举类型的元素。如果这个字段代表了一个枚举类型的元素，那么该方法返回true，否则返回false。

语法

public boolean isEnumConstant()

参数： 此方法不接受任何东西。
返回 ：此方法在此字段代表一个枚举类型的元素时返回 真 。

下面的程序说明了isEnumConstant()方法：

程序1 :

// 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

程序2

// 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

参考文献 ： https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Field.html#isEnumConstant-