Java中的类 isAnnotation() 方法及示例

Java.lang.Class 类的isAnnotation()方法用于检查该类是否为Annotation 类型。如果这个 Class 是 Annotation 类型，则该方法返回 true。否则返回 false。
句法：

public boolean isAnnotation()

参数：此方法不接受任何参数。
返回值：如果这个 Class 是 Annotation 类型，这个方法返回true 。否则返回false 。
下面的程序演示了 isAnnotation() 方法。
示例 1：

Java

// Java program to demonstrate isAnnotation() method
 
public class Test {
    public static void main(String[] args)
        throws ClassNotFoundException
    {
 
        // returns the Class object for this class
        Class myClass = Class.forName("Test");
 
        System.out.println("Class represented by myClass: "
                           + myClass.toString());
 
        // Check if this class is an annotation
        // using isAnnotation() method
        System.out.println("Is Test an annotation: "
                           + myClass.isAnnotation());
    }
}

输出：

Class represented by myClass: class Test
Is Test an annotation: false

示例 2：

Java

// Java program to demonstrate isAnnotation() method
 
// declaring an Annotation Type
@interface A {
    // Annotation element definitions
}
 
public class Test {
    public static void main(String[] args)
        throws ClassNotFoundException
    {
 
        // returns the Class object for A
        Class myClass = A.class;
 
        // Check if myClass is an annotation
        // using isAnnotation() method
        System.out.println("Is A an annotation: "
                           + myClass.isAnnotation());
    }
}

输出：

Is A an annotation: true

参考： https://docs.oracle.com/javase/9/docs/api/ Java/lang/Class.html#isAnnotation–