Java Field isEnumConstant()用法及代碼示例

java.lang.reflect.Field的isEnumConstant()方法，用於檢查此字段是否表示枚舉類型的元素。如果此字段表示枚舉類型的元素，則方法返回true，否則返回false。

用法:

public boolean isEnumConstant()

參數：此方法接受不接受任何內容。

返回：僅當此字段表示枚舉類型的元素時，此方法才返回true。

以下示例程序旨在說明isEnumConstant()方法：
示例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"); 
        } 
    } 
}

輸出：

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

示例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 
    } 
}

輸出：

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

參考文獻： https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Field.html#isEnumConstant–

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注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 Field isEnumConstant() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。