springmvc自定义异常处理器

当dispatchServlet接收到controller抛出的异常时，会将异常交由 HandlerExceptionResolver

异常处理器处理！我们可以创建自定义异常处理器实现该接口来处理自定义异常

1）自定义异常类

public class MyException extends Exception {
    // 异常信息
    private String message;
 
    public MyException() {
       super();
    }
 
    public MyException(String message) {
       super();
       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

public class CustomHandleException implements HandlerExceptionResolver {
 
    @Override
   public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,
           Exception exception) {
       // 定义异常信息
       String msg;
 
       // 判断异常类型
       if (exception instanceof MyException) {
           // 如果是自定义异常，读取异常信息
           msg = exception.getMessage();
       } else {
           // 如果是运行时异常，则取错误堆栈，从堆栈中获取异常信息
           Writer out = new StringWriter();
           PrintWriter s = new PrintWriter(out);
           exception.printStackTrace(s);
           msg = out.toString();
 
       }
 
       // 把错误信息发给相关人员,邮件,短信等方式
       // TODO
 
       // 返回错误页面，给用户友好页面显示错误信息
       ModelAndView modelAndView = new ModelAndView();
       modelAndView.addObject("msg", msg);
       modelAndView.setViewName("error");
 
       return modelAndView;
    }
}

3）在springmvc.xml中配置异常处理器

<!-- 配置全局异常处理器 -->
<bean
id="customHandleException" class="cn.itcast.ssm.exception.CustomHandleException"/>

4）定制错误页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
 
    <h1>系统发生异常了！</h1>
    <br />
    <h1>异常信息</h1>
    <br />
    <h2>${msg }</h2>
 
</body>
</html>

5）测试异常处理

@RequestMapping(value = "/item/itemlist.action")
public ModelAndView itemList() throws MyException{
        
        List<Items> list = itemService.selectItemsList();
        
        if(true){
            throw new MyException("商品列表不能为空！！");
        }
        
        ModelAndView mav = new ModelAndView();
        mav.addObject("itemList", list);
        mav.setViewName("itemList");
        return mav;
    }