SpringMVC的异常处理

异常处理的思路

Controller调用Service，Service调用Dao，异常都是向上抛出的，最终有DispatcherServlet找异常处理器进行处理。

实现步骤

1. 编写自定义异常类（做提示信息的）

   public class MyException extends Exception{
   
       private String message;
   
       public MyException(String message) {
           this.message = message;
       }
   
       @Override
       public String getMessage() {
           return message;
       }
   
       public void setMessage(String message) {
           this.message = message;
       }
   }

2. 编写异常处理器 实现 HandlerExceptionResolver 接口

   public class MyExceptionResolver implements HandlerExceptionResolver {
       @Override
       public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
           //获取到异常对象
           MyException exception;
           if (e instanceof MyException){
               exception = (MyException) e;
           }else {
               exception = new MyException("出错了");
           }
   
   
           //创建ModelAndView对象
           ModelAndView mv = new ModelAndView("error");
           mv.addObject("errorMsg", exception.getMessage());
           return mv;
       }
   }

3. 在springmvc.xml配置异常处理器

   <bean class="com.xzxj.exception.MyExceptionResolver"/>

再出异常就会跳转到/WEB-INF/jsp/error.jsp页面提示错误