springmvc异常处理器和拦截器

一、异常处理器

　　1、实现HandlerExceptionResolver接口

package com.wuxi.exceptions;

import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class RequestExceptionResolver implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
        ModelAndView mv = new ModelAndView();
        mv.addObject("errorMsg", e.getMessage());//错误信息
        mv.setViewName("error");//请求转发的页面
        return mv;
    }
}

　　2、springmvc的xml配置文件

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--扫描组件-->
    <context:component-scan base-package="com.wuxi"></context:component-scan>
    <!--视图解析器-->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
    <!--参数类型装换器-->
    <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="com.wuxi.utils.StringToDateConverter"></bean>
            </set>
        </property>
    </bean>
    <!--配置调度器不拦截静态资源-->
    <mvc:resources mapping="/css/**" location="/css/"></mvc:resources>
    <mvc:resources mapping="/images/**" location="/images/"></mvc:resources>
    <mvc:resources mapping="/js/**" location="/js/"></mvc:resources>
    <!--配置文件解析器对象-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10485760"></property>
    </bean>
    <!--异常处理器-->
    <bean id="requestExceptionResolver" class="com.wuxi.exceptions.RequestExceptionResolver"></bean>
    <!--开启springmvc框架注解的支持-->
    <mvc:annotation-driven conversion-service="conversionService"></mvc:annotation-driven>
</beans>

二、拦截器

　　1、实现HandlerInterceptor接口

package com.wuxi.interceptors;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ControllerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("controller的方法执行之前执行");
        return true;//true：放行；false：拦截
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("controller的方法执行之后执行");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("jsp执行之后执行");
    }
}

　　2、springmvc的xml配置文件 

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--扫描组件-->
    <context:component-scan base-package="com.wuxi"></context:component-scan>
    <!--视图解析器-->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
    <!--参数类型装换器-->
    <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="com.wuxi.utils.StringToDateConverter"></bean>
            </set>
        </property>
    </bean>
    <!--配置调度器不拦截静态资源-->
    <mvc:resources mapping="/css/**" location="/css/"></mvc:resources>
    <mvc:resources mapping="/images/**" location="/images/"></mvc:resources>
    <mvc:resources mapping="/js/**" location="/js/"></mvc:resources>
    <!--配置文件解析器对象-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10485760"></property>
    </bean>
    <!--异常处理器-->
    <bean id="requestExceptionResolver" class="com.wuxi.exceptions.RequestExceptionResolver"></bean>
    <!--拦截器-->
    <mvc:interceptors>
        <!--可配置多个拦截器，执行顺序pre1->pre2->controller->post2->post1->jsp->after2->after1-->
        <mvc:interceptor>
            <!--拦截的资源路径-->
            <mvc:mapping path="/**"/>
            <!--不拦截的资源路径-->
            <!--<mvc:exclude-mapping path="/hello"/>-->
            <bean class="com.wuxi.interceptors.ControllerInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>
    <!--开启springmvc框架注解的支持-->
    <mvc:annotation-driven conversion-service="conversionService"></mvc:annotation-driven>
</beans>