java 反射获取指定注解修饰的field信息

最新推荐文章于 2025-07-19 09:07:21 发布

原创最新推荐文章于 2025-07-19 09:07:21 发布 · 1k 阅读

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该博客展示了如何在Java中使用注解(@Cherry)并进行反射操作。通过注解实体类Water的字段，然后在测试类中获取注解信息，演示了注解的获取与字段访问。内容涉及注解的定义、应用以及反射在获取注解和字段值时的使用方法。

注解:

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Cherry {

    String value() default "default";

}

实体类:

@Data
public class Water {


    private String name;

    @Cherry
    private Double price;

    @Cherry(value = "test")
    private String tag;


}

测试:

public class GetAnno {
    public static void main(String[] args) throws IllegalAccessException {
        Water water = new Water();
        water.setPrice(100D);
        water.setTag("促销");

        //Class<?> clz = Water.class;
        Class<?> clz = water.getClass();
        Field[] declaredFields = clz.getDeclaredFields();
        for (Field declaredField : declaredFields) {
            Cherry annotation = declaredField.getAnnotation(Cherry.class);
            if(annotation != null){
                System.out.println(annotation);
                declaredField.setAccessible(true);
                if(declaredField.getType() == Double.class){
                    System.out.println(true);
                }
                System.out.println(declaredField.getType());
                Object o = declaredField.get(water);
                System.out.println(o.getClass());
                System.out.println(o);
                System.out.println("------------------------------");
            }
        }
    }
}

输出:

@com.luo.project0109.test0908.Cherry(value=default)
true
class java.lang.Double
class java.lang.Double
100.0
------------------------------
@com.luo.project0109.test0908.Cherry(value=test)
class java.lang.String
class java.lang.String
促销
------------------------------

Process finished with exit code 0