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    3. SpringMVC之异常处理（四）

    SpringMVC之异常处理（四）

    科技2022-07-20  126

    SpringMVC之异常处理

    一、异常处理思路二、异常处理步骤1. 编写异常类和错误页面2.自定义异常类2. 自定义异常处理器3. 配置异常处理器4.执行结果

    一、异常处理思路

    Controller调用service，service调用dao，异常都是向上抛出的，最终有DispatcherServlet找异常处理器进行异常的处理。

    二、异常处理步骤

    1. 编写异常类和错误页面

    UserController

    package com.hzxy.controller; import cn.itcast.exception.SysException; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping("/user") public class UserController { @RequestMapping("/testException") public String testException() throws SysException{ System.out.println("testException执行了..."); try { // 模拟异常 int a = 10/0; } catch (Exception e) { // 打印异常信息 e.printStackTrace(); // 抛出自定义异常信息 throw new SysException("查询所有用户出现错误了..."); } return "success"; } }

    error.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %> <html> <head> <title>Title</title> </head> <body> ${errorMsg} </body> </html>

    2.自定义异常类

    package com.hzxy.exception; /** * 自定义异常类 */ public class SysException extends Exception{ // 存储提示信息的 private String message; public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public SysException(String message) { this.message = message; } }

    2. 自定义异常处理器

    SysExceptionResolver

    package con.hzxy.exception; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 异常处理器 */ public class SysExceptionResolver implements HandlerExceptionResolver{ /** * 处理异常业务逻辑 * @param request * @param response * @param handler * @param ex * @return */ public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { // 获取到异常对象 SysException e = null; if(ex instanceof SysException){ e = (SysException)ex; }else{ e = new SysException("系统正在维护...."); } // 创建ModelAndView对象 ModelAndView mv = new ModelAndView(); mv.addObject("errorMsg",e.getMessage()); mv.setViewName("error"); return mv; } }

    3. 配置异常处理器

    springmvc.xml

    <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- 开启注解扫描 --> <context:component-scan base-package="cn.itcast"/> <!-- 视图解析器对象 --> <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/pages/"/> <property name="suffix" value=".jsp"/> </bean> <!--前端控制器，哪些静态资源不拦截--> <mvc:resources location="/css/" mapping="/css/**"/> <mvc:resources location="/images/" mapping="/images/**"/> <mvc:resources location="/js/" mapping="/js/**"/> <!--配置异常处理器--> <bean id="sysExceptionResolver" class="cn.itcast.exception.SysExceptionResolver"/> <!-- 开启SpringMVC框架注解的支持 --> <mvc:annotation-driven /> </beans>

    4.执行结果

    Processed: 0.010, SQL: 8