记录一下 关于参数解析器 会话请求上下文注入数据所有 controller 均可接收

需求：需要在拦截器中 认证用户身份并且把用户 但是在控制器层需要到用户Dao的数据时 还得 去操作Dao或者 从session 中取，如果存在web无状态情况 即无session 时则需要把数据存入当前会话请求的上下文中；

解决方法：

第一步、创建ArgumentResolver 类

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public class ArgumentResolver implements WebArgumentResolver {     @Override     public Object resolveArgument(MethodParameter methodParameter, NativeWebRequest nativeWebRequest) throws Exception {         Class<?> parameterType = methodParameter.getParameterType();         if (parameterType != null){             HttpServletRequest request = nativeWebRequest.getNativeRequest(HttpServletRequest.class);             if (parameterType.equals(UserDO.class)){                 // 如果数据对象是 userDO 则直接从 请求上下文中获取数据返回                 return request.getAttribute("userData");             }         }         // 正常返回 请求数据         return UNRESOLVED;     } }

　第二步、创建拦截器类UserInterceptor

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public class UserInterceptor implements HandlerInterceptor {         @Override     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {         // 这里应该是 取 request.getHeaders 里面的token 取 userID 然后进行查询 返回 UserDO         UserDO userDO = ...;         //设置返回页面类型和编码         response.setContentType("text/html; charset=UTF-8");         if (userDO != null){             request.setAttribute("userData",userDO);             return true;         }         // 认证失败         response.sendRedirect(request.getContextPath() + "/passport/login");         return false;     }  }

　第三步、创建配置类

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@Configuration public class WebConfig extends WebMvcConfigurationSupport {         @Override     protected void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {         argumentResolvers.add(new ServletWebArgumentResolverAdapter(new ArgumentResolver()));         super.addArgumentResolvers(argumentResolvers);     }    @Override     protected void addInterceptors(InterceptorRegistry registry) {         InterceptorRegistration registration = registry.addInterceptor(new UserInterceptor()); //        registration.excludePathPatterns( // //        );         registration.addPathPatterns(                 "/user/**",                 "/passport/**"         );         super.addInterceptors(registry);     } }

　第四步、在controller中使用

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@GetMapping(value = "/account")     public String account(             UserDO userDO     ){         System.out.println("userData = " + userDO); }

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