详解SpringMVC中的异常处理

目录

• 1. SpringMVC默认三个异常处理类

• 2. @ExceptionHandler注解异常

• 3. @ResponseStatus注解异常

• 4. DefaultHandlerExceptionResolver默认异常

• 5. 没有找到对应异常处理类

1. SpringMVC默认三个异常处理类

• ExceptionHandlerExceptionResolver：处理@ExceptionHandler注解

• ResponseStatusExceptionResolver：处理@ResponseStatus注解

• DefaultHandlerExceptionResolver：处理SpringMVC自带的异常
  

如果以上3个异常解析器都无法处理，会上抛给tomcat，处理异常内部的默认工作流程：所有异常解析器依次尝试解析，解析完成进行后续操作，解析失败，下一个解析器继续尝试解析。

2. @ExceptionHandler注解异常

@ExceptionHandler标注在方法上

• 方法上写一个Exception用来接收发生的异常。

• 要携带异常信息不能给参数位置写Model，正确的做法是返回ModelAndView。

• 如果有多个@ExceptionHandler都能处理这个异常，精确优先。

@ExceptionHandler(value = { ArithmeticException.class, NullPointerException.class })
// 告诉SpringMVC,这个方法专门处理这个类发送的所有异常
public ModelAndView handleException01(Exception exception) {
 System.out.println("handleException01..." + exception);
 ModelAndView view = new ModelAndView("myerror");
 view.addObject("ex", exception);  
 return view;
}

@ExceptionHandler统一异常处理

• 将@ExceptionHandler放在一个单独的类中，进行全局异常处理

• 统一异常管理类需要通过@ControllerAdvice注解加入IoC容器中

• 全局异常处理与本类异常处理同时存在，本类优先

@ControllerAdvice
public class MyException {
 // 处理空指针异常
 @ExceptionHandler(value = { NullPointerException.class })
 public ModelAndView handleException01(Exception exception) {
   System.out.println("全局的handleException01..." + exception);
   ModelAndView view = new ModelAndView("myerror");
   view.addObject("ex", exception);
   return view;
 }

// 处理算数异常
 @ExceptionHandler(value = { ArithmeticException.class })
 public ModelAndView handleException02(Exception exception) {
   System.out.println("全局的handleException02..." + exception);
   ModelAndView view = new ModelAndView("myerror");
   view.addObject("ex", exception);
   return view;
 }
}

3. @ResponseStatus注解异常

@ResponseStatus注解标注在自定义异常上，用于设置自定义异常信息

@ResponseStatus(reason = "用户被拒绝登录", value = HttpStatus.NOT_ACCEPTABLE)
public class UsernameNotFoundException extends RuntimeException {
 private static final long serialVersionUID = 1L;
}

4. DefaultHandlerExceptionResolver默认异常

DefaultHandlerExceptionResolver包含以下默认异常

源码:
public class DefaultHandlerExceptionResolver extends AbstractHandlerExceptionResolver {
 ...
 @Override
 protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,
     Object handler, Exception ex) {

try {
     if (ex instanceof NoSuchRequestHandlingMethodException) {
       return handleNoSuchRequestHandlingMethod((NoSuchRequestHandlingMethodException) ex, request, response,
           handler);
     }
     else if (ex instanceof HttpRequestMethodNotSupportedException) {
       return handleHttpRequestMethodNotSupported((HttpRequestMethodNotSupportedException) ex, request,
           response, handler);
     }
     else if (ex instanceof HttpMediaTypeNotSupportedException) {
       return handleHttpMediaTypeNotSupported((HttpMediaTypeNotSupportedException) ex, request, response,
           handler);
     }
     else if (ex instanceof HttpMediaTypeNotAcceptableException) {
       return handleHttpMediaTypeNotAcceptable((HttpMediaTypeNotAcceptableException) ex, request, response,
           handler);
     }
     else if (ex instanceof MissingPathVariableException) {
       return handleMissingPathVariable((MissingPathVariableException) ex, request,
           response, handler);
     }
     else if (ex instanceof MissingServletRequestParameterException) {
       return handleMissingServletRequestParameter((MissingServletRequestParameterException) ex, request,
           response, handler);
     }
     else if (ex instanceof ServletRequestBindingException) {
       return handleServletRequestBindingException((ServletRequestBindingException) ex, request, response,
           handler);
     }
     else if (ex instanceof ConversionNotSupportedException) {
       return handleConversionNotSupported((ConversionNotSupportedException) ex, request, response, handler);
     }
     else if (ex instanceof TypeMismatchException) {
       return handleTypeMismatch((TypeMismatchException) ex, request, response, handler);
     }
     else if (ex instanceof HttpMessageNotReadableException) {
       return handleHttpMessageNotReadable((HttpMessageNotReadableException) ex, request, response, handler);
     }
     else if (ex instanceof HttpMessageNotWritableException) {
       return handleHttpMessageNotWritable((HttpMessageNotWritableException) ex, request, response, handler);
     }
     else if (ex instanceof MethodArgumentNotValidException) {
       return handleMethodArgumentNotValidException((MethodArgumentNotValidException) ex, request, response,
           handler);
     }
     else if (ex instanceof MissingServletRequestPartException) {
       return handleMissingServletRequestPartException((MissingServletRequestPartException) ex, request,
           response, handler);
     }
     else if (ex instanceof BindException) {
       return handleBindException((BindException) ex, request, response, handler);
     }
     else if (ex instanceof NoHandlerFoundException) {
       return handleNoHandlerFoundException((NoHandlerFoundException) ex, request, response, handler);
     }
   }
   catch (Exception handlerException) {
     if (logger.isWarnEnabled()) {
       logger.warn("Handling of [" + ex.getClass().getName() + "] resulted in Exception", handlerException);
     }
   }
   return null;
 }
 ...
}

如下HttpRequestMethodNotSupportedException请求方式不对。使用GET对POST方法进行访问

@RequestMapping(value = "/handle03", method = RequestMethod.POST)
public String postMethod() {
 return "success";
}

5. 没有找到对应异常处理类

若没有对应异常处理类，会进入对应服务器错误页面

来源：https://segmentfault.com/a/1190000039411231