Java 中的 Field isEnumConstant()方法，带示例
原文:https://www . geesforgeks . org/field-isenumconstant-method-in-Java-with-examples/
java.lang.reflect.Field 的 isEnumConstant() 方法，用于检查该字段是否表示枚举类型的元素。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。
语法:
public boolean isEnumConstant()
参数:此方法不接受任何东西。
返回:当且仅当该字段表示枚举类型的元素时，该方法返回真。
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");
}
}
}
Output:
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: $VALUES; isEnumConstant: false
程序 2:
// Java program to illustrate
// isEnumConstant () method
import java.lang.reflect.Field;
public class GFG {
public static void main(String[] args)
throws NoSuchFieldException
{
// get all declared fields of Symbols class
Field[] declaredFields
= Symbols.class.getDeclaredFields();
// loop through Field array
// and print Field name and
// check whether the field is EnumConstant
for (int i = 0; i < declaredFields.length; i++) {
System.out.print(
"Field --> Name: "
+ declaredFields[i].getName()
+ "; isEnumConstant: "
+ declaredFields[i]
.isEnumConstant()
+ "\n");
}
}
private static enum Symbols {
Alpha,
Beta,
Gamma
}
}
Output:
Field --> Name: Alpha; isEnumConstant: true
Field --> Name: Beta; isEnumConstant: true
Field --> Name: Gamma; isEnumConstant: true
Field --> Name: ENUM$VALUES; isEnumConstant: false
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