Spring MVC 多种异常处理

Spring MVC 提供了多种灵活的异常处理机制，确保应用能够优雅地处理错误并返回友好的响应。

异常处理方式概览

@ExceptionHandler 局部处理

在Controller内部声明异常处理方法：

@RestController
@RequestMapping("/user")
public class UserController {

    @GetMapping("/{id}")
    public User getUser(@PathVariable Long id) {
        User user = userService.findById(id);
        if (user == null) {
            throw new UserNotFoundException("用户不存在");
        }
        return user;
    }

    @ExceptionHandler(UserNotFoundException.class)
    public ResponseEntity<String> handleUserNotFound(UserNotFoundException e) {
        return ResponseEntity.status(404).body(e.getMessage());
    }

    @ExceptionHandler(Exception.class)
    public ResponseEntity<String> handleException(Exception e) {
        return ResponseEntity.status(500).body("服务器内部错误");
    }
}

@ControllerAdvice 全局处理

创建全局异常处理类，统一管理所有Controller异常：

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(RuntimeException.class)
    @ResponseBody
    public ResponseEntity<Map<String, Object>> handleRuntimeException(RuntimeException e) {
        Map<String, Object> result = new HashMap<>();
        result.put("code", 500);
        result.put("message", e.getMessage());
        result.put("timestamp", System.currentTimeMillis());
        return ResponseEntity.status(500).body(result);
    }

    @ExceptionHandler(IllegalArgumentException.class)
    @ResponseBody
    public ResponseEntity<Map<String, Object>> handleIllegalArgument(IllegalArgumentException e) {
        Map<String, Object> result = new HashMap<>();
        result.put("code", 400);
        result.put("message", e.getMessage());
        return ResponseEntity.badRequest().body(result);
    }

    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseBody
    public ResponseEntity<Map<String, Object>> handleValidation(MethodArgumentNotValidException e) {
        Map<String, Object> result = new HashMap<>();
        result.put("code", 400);
        result.put("message", "参数校验失败");
        result.put("errors", e.getBindingResult().getFieldErrors());
        return ResponseEntity.badRequest().body(result);
    }
}

HandlerExceptionResolver 接口实现

实现自定义异常解析器：

@Component
public class CustomExceptionResolver implements HandlerExceptionResolver {

    @Override
    public ModelAndView resolveException(HttpServletRequest request,
                                         HttpServletResponse response,
                                         Object handler,
                                         Exception ex) {
        response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        response.setContentType("application/json;charset=UTF-8");

        try {
            Map<String, Object> error = new HashMap<>();
            error.put("code", 500);
            error.put("message", ex.getMessage());
            error.put("path", request.getRequestURI());

            ObjectMapper mapper = new ObjectMapper();
            response.getWriter().write(mapper.writeValueAsString(error));
        } catch (IOException e) {
            e.printStackTrace();
        }

        return new ModelAndView();
    }
}

SimpleMappingExceptionResolver 配置

适用于传统Web应用，异常发生时跳转到指定错误页面：

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Bean
    public SimpleMappingExceptionResolver exceptionResolver() {
        SimpleMappingExceptionResolver resolver = new SimpleMappingExceptionResolver();

        Properties mappings = new Properties();
        mappings.setProperty("UserNotFoundException", "error/404");
        mappings.setProperty("UnauthorizedException", "error/403");
        mappings.setProperty("Exception", "error/500");

        resolver.setExceptionMappings(mappings);
        resolver.setDefaultErrorView("error/default");
        resolver.setExceptionAttribute("exception");

        return resolver;
    }
}

异常处理优先级

1. @ExceptionHandler（Controller内） - 最高优先级
2. @ControllerAdvice中的@ExceptionHandler - 次优先级
3. HandlerExceptionResolver - 最低优先级

局部@ExceptionHandler会覆盖全局@ControllerAdvice中的同类型异常处理。

要点总结

• @ExceptionHandler适用于Controller内部特定异常处理
• @ControllerAdvice是推荐的全局异常处理方式
• HandlerExceptionResolver提供底层定制能力
• SimpleMappingExceptionResolver适合传统页面跳转场景
• 优先级：局部 > 全局 > 框架默认