自定义SimpleMappingExceptionResolver实现个性化的异常处理

Spring MVC 的SimpleMappingExceptionResolver是一个简单的异常处理bean，说他简单是因为SimpleMappingExceptionResolver只能获得内置的异常信息，用户无法将自定义的异常信息带到页面上供用户查看，且SimpleMappingExceptionResolver不支持ajax的异常处理。为了能够让异常体制更具个性化。我们常做的方法是实现HandlerExceptionResolver接口自定义自己的异常处理器。下面介绍另外一种方法：重写SimpleMappingExceptionResolver来实现异常的个性化。

SimpleMappingExceptionResolver异常处理其核心是doResolveException()

protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex) {

String viewName = this.determineViewName(ex, request);

if(viewName != null) {

Integer statusCode = this.determineStatusCode(request, viewName);

if(statusCode != null) {

this.applyStatusCodeIfPossible(request, response, statusCode.intValue());

}

return this.getModelAndView(viewName, ex, request);

} else {

return null;

}

}
所以我们要做的就是重写这个方法

package com.me.common.exception;

import com.alibaba.fastjson.JSON;

import com.alibaba.fastjson.serializer.SerializerFeature;

import java.io.IOException;

import java.util.Properties;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.me.endpoint.GrantResult;

import org.apache.commons.lang3.StringUtils;

import org.springframework.web.bind.annotation.ResponseBody;

import org.springframework.web.method.HandlerMethod;

import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.handler.SimpleMappingExceptionResolver;

public class MyExceptionResolver extends SimpleMappingExceptionResolver {

private String defaultErrorView;

private Properties exceptionMappings;

public MyExceptionResolver() {

}

@Override

public void setDefaultErrorView(String defaultErrorView) {

this.defaultErrorView = defaultErrorView;

super.setDefaultErrorView(defaultErrorView);

}

@Override

public void setExceptionMappings(Properties exceptionMappings) {

this.exceptionMappings = exceptionMappings;

super.setExceptionMappings(exceptionMappings);

}

@Override

protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex) {

boolean isAjax = this.isJsonRequest(handler);

return isAjax?this.jsonExceptionHandler(response, ex):this.generalExceptionHandler(request, response, ex);

}

private boolean isJsonRequest(Object handler) {

HandlerMethod method = (HandlerMethod)handler;

ResponseBody body = (ResponseBody)method.getMethodAnnotation(ResponseBody.class);

return body != null;

}

//ajax异步请求

private ModelAndView jsonExceptionHandler(HttpServletResponse response, Exception e) {

ServletOutputStream stream = null;

try {

response.setContentType("application/json");

response.setCharacterEncoding("UTF-8");

response.setHeader("Cache-Control", "no-cache, must-revalidate");

stream = response.getOutputStream();

String errorMsg = "系统出错了";

if(e instanceof GenericException || e instanceof EcouponException){

errorMsg = e.getMessage();

}

stream.write(JSON.toJSONBytes(new GrantResult("faild", errorMsg), new SerializerFeature[]{SerializerFeature.QuoteFieldNames}));

} catch (Exception var16) {

} finally {

if(stream != null) {

try {

stream.close();

} catch (IOException var15) {

var15.printStackTrace();

}

}

}

return new ModelAndView();

}

//普通请求

private ModelAndView generalExceptionHandler(HttpServletRequest request, HttpServletResponse response, Exception ex) {

String errorLog = String.format("web请求[%s]发生异常:%s", new Object[]{request.getServletPath(), ex.getMessage()});

this.logger.error(errorLog, ex);

ModelAndView mav = new ModelAndView();

String errorMsg = "系统出错了";

if(ex instanceof GenericException || ex instanceof EcouponException){

errorMsg = ex.getMessage();

}

mav.addObject("msg", errorMsg);

String name = ex.getClass().getName();

String path = this.exceptionMappings.getProperty(name);

String wrapperPath = StringUtils.isEmpty(path)?defaultErrorView:path;

mav.setViewName(wrapperPath);

return mav;

}

}
最后配置该bean：

<bean class="com.me.common.exception.XExceptionResolver">

<!-- view name resolved using bean of type InternalResourceViewResolver (declared in mvc-view-config.xml) -->

<property name="defaultErrorView" value="exception"/>

<!-- needed otherwise exceptions won't be logged anywhere -->

<property name="exceptionMappings">

<props>

<prop key="com.me.common.exception.GenericException">error/error</prop>

<prop key="com.me.common.exception.EcouponException">error/error</prop>

<prop key="java.lang.Exception">error/error</prop>

</props>

</property>

</bean>