Spring HandlerMethodArgumentResolver 未执行

Question

我正在使用 Spring MVC 3.2.2

我已经定义了一个像这样的自定义 HandlerMethodArgumentResolver 类

public class CurrentUserArgumentResolver implements HandlerMethodArgumentResolver {

  public CurrentUserArgumentResolver() {
    System.out.println("Ready");
  }

  @Override
  public boolean supportsParameter(MethodParameter parameter) {
    return parameter.hasParameterAnnotation(CurrentUser.class);
  }

  @Override
  public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
        NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {

      Principal principal = webRequest.getUserPrincipal();
      System.out.println("*** Principal ***: " + principal);
      return principal;
  }
}

并将以下内容添加到我的 app-servlet.xml

<mvc:annotation-driven>
  <mvc:argument-resolvers>
    <beans:bean class="my.package.CurrentUserArgumentResolver" lazy-init="false"/>
  </mvc:argument-resolvers>
</mvc:annotation-driven>

并为 CurrentUser 创建了注解

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface CurrentUser {

}

当我启动应用程序时，会构造类，因为我可以看到日志消息“就绪”，但是当我这样注释 Controller 方法时解析器不会执行(在具有 @Controller 注释的类中)

@RequestMapping(method = RequestMethod.POST, value = "/update")
public ModelAndView update(@RequestParam MultipartFile background, @CurrentUser Principal principal) {
 ...
}

如果我在 CurrentUserArgumentResolver 类中的任一方法上设置断点，都不起作用。所以不确定我错过了什么？

Answer 1

如果有人想要将自定义处理程序优先于 spring 添加的默认处理程序，这里有一个片段可以为我完成，我在 @Configuration 文件中执行此操作

private @Inject RequestMappingHandlerAdapter adapter;

@PostConstruct
public void prioritizeCustomArgumentMethodHandlers () {
  List<HandlerMethodArgumentResolver> argumentResolvers = 
      new ArrayList<> (adapter.getArgumentResolvers ());
  List<HandlerMethodArgumentResolver> customResolvers = 
      adapter.getCustomArgumentResolvers ();
  argumentResolvers.removeAll (customResolvers);
  argumentResolvers.addAll (0, customResolvers);
  adapter.setArgumentResolvers (argumentResolvers);
}