在服务器端出现异常，或者客户端请求出错时，直接返回异常信息对用户来说是非常不友好的，我们需要对异常信息进行统一处理
1、使用 @ControllerAdvice 注解
使用 @ControllerAdvice 注解的控制层的全局统一异常处理
@ControllerAdvice
public class GlobalExceptionHandler {@ExceptionHandler(Exception.class)public ModelAndView customException(Exception e) {ModelAndView mav = new ModelAndView();// 跳转到错误页面mav.setViewName("error");return mav;}
}
@ControllerAdvice 表示这是一个控制器增强类，当控制器发生异常且符合类中定义的拦截异常类，将会被拦截
@ExceptionHandler 则是定义拦截的异常类，可以是自定义异常类，例如：
@ExceptionHandler(value = MyException.class)
@ResponseBody
public JSONObject myErrorHandler(MyException exception) {JSONObject res = new JSONObject();res.put("code", exception.getCode());res.put("msg", exception.getMsg());return res;
}
当然，我们可以不返回页面，只返回异常信息
使用 @ControllerAdvice 只能捕获 Controller 层的异常，前提是 Controller 层没有对异常做 catch 处理
2、实现 ErrorController 接口
@Controller
@RequestMapping(value = "error")
@EnableConfigurationProperties({ServerProperties.class})
public class ExceptionController implements ErrorController {private ErrorAttributes errorAttributes;@Autowiredprivate ServerProperties serverProperties;/*** 初始化ExceptionController** @param errorAttributes*/@Autowiredpublic ExceptionController(ErrorAttributes errorAttributes) {Assert.notNull(errorAttributes, "ErrorAttributes must not be null");this.errorAttributes = errorAttributes;}/*** 定义404的ModelAndView** @param request* @param response* @return*/@RequestMapping(produces = "text/html", value = "404")public ModelAndView errorHtml404(HttpServletRequest request, HttpServletResponse response) {response.setStatus(getStatus(request).value());Map<String, Object> model = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.TEXT_HTML));return new ModelAndView("error/404", model);}/*** 定义404的JSON数据** @param request* @return*/@RequestMapping(value = "404")@ResponseBodypublic ResponseEntity<Map<String, Object>> error404(HttpServletRequest request) {Map<String, Object> body = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.TEXT_HTML));HttpStatus status = getStatus(request);return new ResponseEntity<Map<String, Object>>(body, status);}/*** 定义500的ModelAndView** @param request* @param response* @return*/@RequestMapping(produces = "text/html", value = "500")public ModelAndView errorHtml500(HttpServletRequest request, HttpServletResponse response) {response.setStatus(getStatus(request).value());Map<String, Object> model = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.TEXT_HTML));return new ModelAndView("error/500", model);}/*** 定义500的错误JSON信息** @param request* @return*/@RequestMapping(value = "500")@ResponseBodypublic ResponseEntity<Map<String, Object>> error500(HttpServletRequest request) {Map<String, Object> body = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.TEXT_HTML));HttpStatus status = getStatus(request);return new ResponseEntity<Map<String, Object>>(body, status);}/*** 确定是否应包含stacktrace属性** @param request the source request* @param produces the media type produced (or {@code MediaType.ALL})* @return if the stacktrace attribute should be included*/protected boolean isIncludeStackTrace(HttpServletRequest request, MediaType produces) {ErrorProperties.IncludeStacktrace include = this.serverProperties.getError().getIncludeStacktrace();if (include == ErrorProperties.IncludeStacktrace.ALWAYS) {return true;}if (include == ErrorProperties.IncludeStacktrace.ON_TRACE_PARAM) {return getTraceParameter(request);}return false;}/*** 获取错误的信息** @param request* @param includeStackTrace* @return*/private Map<String, Object> getErrorAttributes(HttpServletRequest request, boolean includeStackTrace) {RequestAttributes requestAttributes = new ServletRequestAttributes(request);return this.errorAttributes.getErrorAttributes((WebRequest) requestAttributes, includeStackTrace);}/*** 是否包含trace** @param request* @return*/private boolean getTraceParameter(HttpServletRequest request) {String parameter = request.getParameter("trace");if (parameter == null) {return false;}return !"false".equals(parameter.toLowerCase());}/*** 获取错误编码** @param request* @return*/private HttpStatus getStatus(HttpServletRequest request) {Integer statusCode = (Integer) request.getAttribute("javax.servlet.error.status_code");if (statusCode == null) {return HttpStatus.INTERNAL_SERVER_ERROR;}try {return HttpStatus.valueOf(statusCode);} catch (Exception ex) {return HttpStatus.INTERNAL_SERVER_ERROR;}}/*** 实现错误路径** @return*/@Overridepublic String getErrorPath() {return "";}}
总结
1、@ControllerAdvice 定义多个拦截方法，拦截不同的异常类，并且可以获取抛出的异常信息
2、@ControllerAdvice 只能捕获进入 Controller 层的异常，比如404,401等错误无法捕获
3、ErrorController，该方式几乎可以处理所有的异常，包括未进入控制器的错误，比如404,401等错误
当然，前提是没有对异常做 catch 处理才能捕获到
