请求参数的自定义Spring注释 [英] Custom Spring annotation for request parameters

问题描述

我想编写自定义注释，根据注释修改Spring请求或路径参数。例如，代替此代码：

I would like to write custom annotations, that would modify Spring request or path parameters according to annotations. For example instead of this code:

@RequestMapping(method = RequestMethod.GET)
public String test(@RequestParam("title") String text) {
   text = text.toUpperCase();
   System.out.println(text);
   return "form";
}

我可以注释@UpperCase：

I could make annotation @UpperCase :

@RequestMapping(method = RequestMethod.GET)
   public String test(@RequestParam("title") @UpperCase String text) {
   System.out.println(text);
   return "form";
}

是否可能，如果是，我该怎么办？

Is it possible and if it is, how could I do it ?

推荐答案

正如大家在评论中所说，你可以轻松编写注释驱动的自定义解析器。四个简单的步骤，

As the guys said in the comments, you can easily write your annotation driven custom resolver. Four easy steps,

1. 创建注释，例如

---

---

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface UpperCase {
    String value();
}

1. 写一个解析器，例如

---

---

public class UpperCaseResolver implements HandlerMethodArgumentResolver {

    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.getParameterAnnotation(UpperCase.class) != null;
    }

    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest,
            WebDataBinderFactory binderFactory) throws Exception {
        UpperCase attr = parameter.getParameterAnnotation(UpperCase.class);
        return webRequest.getParameter(attr.value()).toUpperCase();
    }
}

1. 注册一个解析器

---

---

<mvc:annotation-driven>
        <mvc:argument-resolvers>
            <bean class="your.package.UpperCaseResolver"></bean>
        </mvc:argument-resolvers>
</mvc:annotation-driven>

或java config

or the java config

    @Configuration
    @EnableWebMvc
    public class Config extends WebMvcConfigurerAdapter {
    ...
      @Override
      public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
          argumentResolvers.add(new UpperCaseResolver());
      }
    ...
    }

1. 在控制器方法中使用注释，例如

---

---

public String test(@UpperCase("foo") String foo) 

这篇关于请求参数的自定义Spring注释的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！