注解解析

package annotation;

import org.junit.Test;

import java.lang.reflect.Method;
import java.util.Arrays;

/**
 * FileName: AnnotationDemo01
 * Author:   lps
 * Date:     2022/4/23 13:51
 * Sign:刘品水 Q：1944900433
 */

public class AnnotationDemo01 {
    @Test
    public void parseMethod() throws NoSuchMethodException {
        //先得到类对象
        Class c=BookStore.class;
        Method m = c.getDeclaredMethod("test");

        //判断这个类是否存在这个注解
        if (m.isAnnotationPresent(Book.class)){
            //获取该注解对象
            Book book = (Book) m.getDeclaredAnnotation(Book.class);
            System.out.println(book.value());
            System.out.println(book.price());
            System.out.println(Arrays.toString(book.authors()));
        }

    }
}

@Book(value = "《Java学习》",price =188.88,authors = {"刘品水","图书大王"})
class BookStore{
    @Book(value = "《迪迦凹凸曼》",price =18.88,authors = {"图书大王"})
    public void test(){

    }
}

package annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * FileName: Book
 * Author:   lps
 * Date:     2022/4/23 13:51
 * Sign:刘品水 Q：1944900433
 * @author lps
 */
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Book {
    String value();

    double price() default 100;

    String[] authors();
}