Springmvc自定义异常处理器实现流程解析

所属分类：软件编程 / java 阅读数： 41

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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;
  }