在运行时访问注释 [英] Access annotation at runtime

问题描述

如何在main中访问Sample类中的check是true还是false?
我应该在 Main 类中写什么?

How can I access in main whether check in the Sample class is true or false?
What should I write in Main class?

    package annotation;

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

    @Retention(RetentionPolicy.RUNTIME)

    public @interface annotation {
        public String name() default "Jimmy";
        public boolean check() default false;
    }

<小时>

    package annotation;

    @annotation(name = "Jack", check = false)

    public class Sample {

        public String str = "Hi";

        public void printHi(String str) {
            System.out.println(str);
        }
    }

<小时>

    package annotation;

    public class Main {
        public static void main(String[] args) {

        }
    }

推荐答案

使用 Sample.class.getAnnotation(annotation.class) 获取你的注解实例，并调用 check()获取校验值:

System.out.println(Sample.class.getAnnotation(annotation.class).check());

请注意，类应该以大写字母开头，并且将注释命名为annotation"很容易混淆.

Note that classes should start with an upper-case letter, and that naming an annotation "annotation" is quite confusing.

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