简单的实现登录拦截及统一异常处理（自定义异常）

webmvc配置类：

@Configurationpublic class WebMvcConfig extends WebMvcConfigurationSupport{@Overrideprotected void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**").excludePathPatterns("/user/login")；}}

注：registry.addInterceptor(拦截器类对象).addPathPatterns("需要拦截的请求路径").excludePathPatterns("可以放行的请求路径");

拦截器类，这里为登录拦截

public class LoginInterceptor implements HandlerInterceptor{@Overridepublic void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)throws Exception {// TODO Auto-generated method stub }@Overridepublic void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)throws Exception {// TODO Auto-generated method stub }@Overridepublic boolean preHandle(HttpServletRequest hServletRequest, HttpServletResponse hServletResponse, Object object) throws Exception {// 案例采用session存储登录用户，所以从session获取登录用户

HttpSession session = hServletRequest.getSession();TUser tUser=(TUser)session.getAttribute("user");

// 判断session里是否能取出用户if(tUser==null) {returnErrorMessage(hServletResponse, "当前操作需要先进行用户登录");return false;}return true;}private void returnErrorMessage(HttpServletResponse response, String errorMessage) throws IOException {response.setCharacterEncoding("utf-8");Map<String, Object> var=new HashMap<>();var.put("success", false);var.put("errorMessage", errorMessage);response.setContentType("application/json");PrintWriter out = response.getWriter();ObjectMapper mapper = new ObjectMapper();String jsonOfRST =mapper.writeValueAsString(var);out.print(jsonOfRST);out.flush();}}

到这里实现了简单的登录拦截，但是上面通过response对象获取的输出流来写入错误信息，下面采用自定义异常来处理

异常类

public class UnloggedException extends RuntimeException{private static final long serialVersionUID = 181074719716690931L;public UnloggedException() {super("当前操作需要先进行登录");}}

修改拦截器类的preHandle方法，于是returnErrorMessage方法可以去掉了

@Overridepublic boolean preHandle(HttpServletRequest hServletRequest, HttpServletResponse hServletResponse, Object object) throws Exception {HttpSession session = hServletRequest.getSession();TUser tUser=(TUser)session.getAttribute("user");if(tUser==null) {throw new UnloggedException();}return true;}

最后配置异常处理类

@ControllerAdvice@ResponseBodypublic class GlobalExceptionHandler {@ExceptionHandlerpublic JSONObject handleException(Exception e) {return ActionHelper.responseFailed(e.getMessage());}}

上面的返回值及ActionHelper为我使用的返回工具类，依赖为com.alibaba的fastjson，版本参考1.2.49。

可以根据实际情况修改返回方式及返回值。

此后所有的异常，都可以通过自定义异常的方式，交由异常处理类来进行处理，返回结果。

如果觉得《简单的实现登录拦截及统一异常处理（自定义异常）》对你有帮助，请点赞、收藏，并留下你的观点哦！