package com.mmall.common;

import com.mmall.exception.PermissionException;

import lombok.extern.slf4j.Slf4j;

import org.springframework.web.servlet.HandlerExceptionResolver;

import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/*必须配置被spring管理，全局异常就会被捕捉 -> spring-servlet.xml*/

@Slf4j

public class SpringExceptionResolver implements HandlerExceptionResolver {

    @Override

    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception e) {

        String url = request.getRequestURL().toString();

        ModelAndView mv;

        String defaultMsg = "System error";

        //如何判断请求时页面请求还是数据请求 .json .page

        //要求项目中所有请求json数据，都是用.json结尾

        if (url.endsWith(".json")){

            //区分使用自定义message还是系统message

            if (e instanceof PermissionException){

                JsonData result = JsonData.fail(e.getMessage());

                mv = new ModelAndView("jsonView", result.toMap());//jsonView 对应dispatcher中的bean id

            }else {

                //输出未知的异常

                log.error("-----unknow json exception! url-----" + url,e);

                JsonData result = JsonData.fail(defaultMsg);

                mv = new ModelAndView("jsonView", result.toMap());

            }

        }else if (url.endsWith(".page")){//page页面使用.page结尾

            log.error("-----unknow page exception! url-----" + url,e);

            JsonData result = JsonData.fail(defaultMsg);

            mv = new ModelAndView("exception", result.toMap());//对应exception.jsp

        }else {

            log.error("-----unknow other exception! url-----" + url,e);

            JsonData result = JsonData.fail(defaultMsg);

            mv = new ModelAndView("jsonView", result.toMap());//默认也返回json格式

        }

        return mv;

    }

}

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:context="http://www.springframework.org/schema/context"

       xmlns:mvc="http://www.springframework.org/schema/mvc"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--上下文注解-->

    <context:annotation-config />

    <!--启动注解驱动的spring mvc 功能-->

    <mvc:annotation-driven/>

    <!--启动包扫描-->

    <context:component-scan base-package="com.mmall.controller" />

    <context:component-scan base-package="com.mmall.service" />

    <!--管理异常处理类 SpringExceptionResolver-->

    <bean class="com.mmall.common.SpringExceptionResolver"/>

    <!-- RequestMapping bean--><!--需要一个Handler来适配-->

    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/>

    <!--处理请求的返回-->

    <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" />

    <bean id="jsonView" class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" />

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix" value="/WEB-INF/views/"/>

        <property name="suffix" value=".jsp" />

    </bean>

</beans>