SpringMVC 异常处理
异常处理思路
系统中异常包括两类：预期异常和运行时异常，前者通过捕获异常从而获取异常信息，后者主要通过规范代码开发、测试通过手段减少运行时异常的发生。
Controller 调用 service，service 调用 dao，异常都是向上抛出的，最终由 DispatcherServlet 寻找异常处理器进行异常的处理。
异常处理流程
自定义异常类和相关页面
package cn.parzulpan.exception;
/**
* @Author : parzulpan
* @Time : 2020-12
* @Desc : 自定义异常类
*/
public class CustomException extends Exception{
private String message; // 异常信息
public CustomException(String message) {
this.message = message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
src/main/webapp/WEB-INF/views/error.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
<title>出错啦</title>
</head>
<body>
出错啦~，${message}
</body>
</html>
src/main/webapp/WEB-INF/views/success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>成功啦</title>
</head>
<body>
成功啦...
</body>
</html>
自定义异常处理器
package cn.parzulpan.exception;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @Author : parzulpan
* @Time : 2020-12
* @Desc : 自定义异常处理器
*/
public class CustomExceptionResolver implements HandlerExceptionResolver {
@Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object o, Exception e) {
e.printStackTrace();
CustomException customException = null;
if (e instanceof CustomException) {
customException = (CustomException) e;
} else {
customException = new CustomException("系统错误！请联系相关人员！");
}
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("message", customException.getMessage());
modelAndView.setViewName("error");
return modelAndView;
}
}
配置异常处理器
src/main/webapp/WEB-INF/dispatcher-servlet.xml
<!-- 配置 异常处理器 -->
<bean id="customExceptionResolver" class="cn.parzulpan.exception.CustomExceptionResolver"/>
测试使用
package cn.parzulpan.web.controller;
import cn.parzulpan.exception.CustomException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
/**
* @Author : parzulpan
* @Time : 2020-12
* @Desc :
*/
@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/testException")
public String testException() throws CustomException {
System.out.println("called testException...");
try {
int a = 10 / 0; //模拟异常
} catch (Exception e) {
throw new CustomException("执行用户查询时出错了...");
}
return "success";
}
}
src/main/webapp/index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<a href="user/testException">模拟异常处理</a>
</body>
</html>