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。
异常处理
先看下项目的目录结构
演示程序异常
index.jsp：
<%-- Created by IntelliJ IDEA. User: Keafmd Date: 2021/2/6 Time: 10:11 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h1>异常处理</h1> <a href="user/testException">testException</a> </body> </html>
UserController类：
package com.keafmd.controller; import com.keafmd.exception.SysException; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import java.sql.SQLOutput; /** * Keafmd * * @ClassName: UserController * @Description: * @author: 牛哄哄的柯南 * @date: 2021-02-06 10:14 */ @Controller @RequestMapping("/user") public class UserController { @RequestMapping("testException") public String testException() throws Exception{ System.out.println("testException执行了。。。"); //模拟异常 int a = 10/0; return "success"; } }
success.jsp：
<%-- Created by IntelliJ IDEA. User: Keafmd Date: 2021/1/30 Time: 15:09 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h1>执行成功</h1> </body> </html>
配置好tomcat后开始执行。
演示效果
点击testException后
这种显示非常不友好，我们需要处理下异常。
异常处理步骤
1、自定义异常类
SysException：
package com.keafmd.exception; /** * Keafmd * * @ClassName: SysException * @Description: 自定义异常类 * @author: 牛哄哄的柯南 * @date: 2021-02-06 10:25 */ public class SysException extends Exception{ //存储提示信息 private String message; public SysException(String message) { this.message = message; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } }
2、自定义异常处理器
SysExceptionResolver：
package com.keafmd.exception; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Keafmd * * @ClassName: SysExceptionResolver * @Description: 异常处理器 * @author: 牛哄哄的柯南 * @date: 2021-02-06 10:32 */ public class SysExceptionResolver implements HandlerExceptionResolver { /** * 处理异常的业务逻辑 * @param httpServletRequest * @param httpServletResponse * @param o * @param e * @return */ @Override public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) { //准备获取到异常对象 SysException se = null; if(e instanceof SysException){ se = (SysException)e; }else{ se = new SysException("系统正在维护,请联系管理员。。。"); } //创建ModelAndView对象 ModelAndView mv = new ModelAndView(); mv.addObject("errorMsg",se.getMessage()); mv.setViewName("error"); return mv; } }
error.jsp：
<%-- Created by IntelliJ IDEA. User: Keafmd Date: 2021/2/6 Time: 10:39 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %> <html> <head> <title>Title</title> </head> <body> ${errorMsg} </body> </html>
3、配置异常处理器
在springmvc.xml里面进行配置：（添加如下配置信息）
<!--配置异常处理器对象--> <bean id="sysExceptionResolver" class="com.keafmd.exception.SysExceptionResolver"/>
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，配置spring创建容器时要扫描的包 --> <context:component-scan base-package="com.keafmd"></context:component-scan> <!-- 配置视图解析器 --> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/pages/"></property> <property name="suffix" value=".jsp"></property> </bean> <!--告诉前端控制器，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/**" /> <!-- 开启SpringMVC框架注解支持，注解配置spring开启注解mvc的支持 --> <mvc:annotation-driven/> <!--配置异常处理器对象--> <bean id="sysExceptionResolver" class="com.keafmd.exception.SysExceptionResolver"/> </beans>
UserController类（包含异常处理）：
package com.keafmd.controller; import com.keafmd.exception.SysException; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import java.sql.SQLOutput; /** * Keafmd * * @ClassName: UserController * @Description: * @author: 牛哄哄的柯南 * @date: 2021-02-06 10:14 */ @Controller @RequestMapping("/user") public class UserController { @RequestMapping("testException") public String testException() throws Exception{ System.out.println("testException执行了。。。"); try { //模拟异常 int a = 10/0; } catch (Exception e) { //控制台打印异常信息 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"; } }
异常处理效果演示
运行效果：
点击testException后，显示我们自定义的异常信息。
以上就是SpringMVC的异常处理的全部内容。
