Spring Boot - Component类中的自定义注释

Question

我真的是春天哲学的新人。在我们的项目中，我们有很多随机字符串，为了使它更容易我想创建自定义注释以将随机字符串注入字段。示例类

@Component
public class Tester{

    @InjectRandomString(length = 25)
    private String randomString;
    public void testRandom() {
        System.out.println(randomString);

    }

}

这是我的BeanPostProcessor类

public class InjectRandomStringAnnotationBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String name) throws BeansException {
        Field[] fields = bean.getClass().getDeclaredFields();
        for (Field field : fields) {
            InjectRandomString annotation = field.getAnnotation(InjectRandomString.class);
            System.out.println(field.getName());
            if(annotation != null){
                System.out.println("NOT NULL");

                int length = annotation.length();
                if(length < 0){
                    throw new IllegalArgumentException("Length is negative");
                }
                String random = UsefulStaff.getRandomString(length);
                field.setAccessible(true);
                ReflectionUtils.setField(field, bean, random);
            }
        }
        return bean;
    }
}

要注册这个课程，我已经使用以下Bean

创建了@Config类

@Bean
    public InjectRandomStringAnnotationBeanPostProcessor randomStringPostProcessor(){
        return new InjectRandomStringAnnotationBeanPostProcessor();
    }

为了测试它，我在RestController中创建了Tester对象

@Autowired
Tester tester;

@RequestMapping(value = "test", method = RequestMethod.GET, produces = "application/json;charset=UTF-8")
    @ResponseBody
    public ResponseEntity<String> test(@RequestParam(name = "message") String meString) throws TimeoutException, SocketTimeoutException, SocketException {

        tester.sendMessageToQueue();
        return ResponseEntity.ok(Enums.Error.SUCCESS.toString());
    }

但每次调用此方法时，我的randomString都等于null。我做错了什么？

@Retention(RetentionPolicy.RUNTIME)
public @interface InjectRandomString {
    int length();
}