基于springmvc的异常处理

   在实际的开发过程中，无论是业务还是数据库都有可能会发生异常。如果每个地方都单独去处理异常，系统的代码耦合度高，工作量大且不好统一，维护的工作量也很大。因此，我们将所有类型的异常处理从各处理过程解耦出来，这样既保证了相关处理过程的功能较单一，也实现了异常信息的统一处理和维护。

本文主要讲述基于实现Spring的异常处理接口HandlerExceptionResolver 自定义自己的异常处理器。

1、web.xml配置异常页面

<error-page><error-code>401</error-code><location>/errorpages/error.jsp</location></error-page><error-page><error-code>403</error-code><location>/errorpages/error.jsp</location></error-page><error-page><error-code>404</error-code><location>/errorpages/error.jsp</location></error-page><error-page><error-code>405</error-code><location>/errorpages/error.jsp</location></error-page><error-page><error-code>500</error-code><location>/errorpages/error.jsp</location></error-page><error-page><error-code>400</error-code><location>/errorpages/error.jsp</location></error-page><error-page><exception-type>java.lang.Exception</exception-type><location>/errorpages/error.jsp</location></error-page>

此处用于配置未捕获的异常

2、自定义注解实现方法内部错误时页面跳转和提示

创建自定义注解

@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface MethodExceptionView {//页面发现异常时跳转的页面String jumpView() default "forward:/errorpages/error.jsp";//页面的提示信息String message() default "操作失败，请刷新再试!";}

3、实现HandlerExceptionResolver接口自定义异常处理类

public class ExceptionHandlerResolver implements HandlerExceptionResolver {private final Log log = LogFactory.getLog(getClass());public ModelAndView resolveException(HttpServletRequest request,HttpServletResponse response, Object handler, Exception exception) {try {String message = null;if (log.isTraceEnabled()) {log.error(exception, exception);} else {log.error(exception);}//异常日志输出StackTraceElement stackTraceElement= exception.getStackTrace()[0];log.error("请求url:" + request.getServletPath());log.error("异常类:" + exception.getClass().getName());log.error("File="+stackTraceElement.getFileName());log.error("Line="+stackTraceElement.getLineNumber());log.error("Method="+stackTraceElement.getMethodName());//ajax请求，返回提示信息if (isAjax(request)) {message = exception.getMessage();addPromptMessageWithAjaxException(request, response, message);return null;}//不处理项目自定义的异常if(exception instanceof AppException || exception instanceof BusinessException) {return new ModelAndView("forward:/errorpages/error.jsp");}//同步请求，代码内部错误时，通过获取方法上的自定义注解进行 页面跳转和信息提示HandlerMethod handlerMethod = (HandlerMethod) handler;  MethodExceptionView methodExceptionView = handlerMethod.getMethod().getAnnotation(MethodExceptionView.class);if(null != methodExceptionView) {ModelAndView mav = new ModelAndView();mav.setViewName(methodExceptionView.jumpView());mav.addObject("message", methodExceptionView.message());return mav;}} catch (Exception e) {}return new ModelAndView("forward:/errorpages/error.jsp");}private void addPromptMessageWithAjaxException(HttpServletRequest request, HttpServletResponse response, String message) {Writer writer = null;JSONObject jsonObject = new JSONObject();jsonObject.put("success", false);jsonObject.put("message", message);System.out.println(message);try {writer = response.getWriter();writer.write(jsonObject.toJSONString());writer.flush();writer.close();} catch (IOException e) {log.error("io close exception", e);} catch (Exception e) {log.error("io close exception", e);}finally {try {writer.flush();writer.close();} catch (IOException e) {}}}/** *  * 验证是否为ajax请求 * @param request * @return */private boolean isAjax(HttpServletRequest request) {return "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));}}

此处除了处理异常外还记录了异常请求和异常产生处，（注:此处无法捕获异常）