回顾

我在之前发布了一篇spring统一返回的文章，最后提到是无法捕获404异常的，这里我们先来测试一下

@RestControllerpublic class TestController {@GetMapping("/test")public String insert22() {return "hello";}}

浏览器请求试一下 http://localhost:8080/xxx 报错

# Whitelabel Error PageThis application has no explicit mapping for /error, so you are seeing this as a fallback.Wed Dec 29 10:14:36 CST 2021There was an unexpected error (type=Not Found, status=404).

springboot的处理方式

springboot处理这个404的异常是在

BasicErrorController

中处理的

@Controller@RequestMapping("${server.error.path:${error.path:/error}}")public class BasicErrorController extends AbstractErrorController {...........@Overridepublic String getErrorPath() {return null;}@RequestMapping(produces = MediaType.TEXT_HTML_VALUE)public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {HttpStatus status = getStatus(request);Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(request, getErrorAttributeOptions(request, MediaType.TEXT_HTML)));response.setStatus(status.value());ModelAndView modelAndView = resolveErrorView(request, response, status, model);return (modelAndView != null) ? modelAndView : new ModelAndView("error", model);}// 包含请求头 "Accept": "application/json" 会往这里走@RequestMappingpublic ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {HttpStatus status = getStatus(request);if (status == HttpStatus.NO_CONTENT) {return new ResponseEntity<>(status);}Map<String, Object> body = getErrorAttributes(request, getErrorAttributeOptions(request, MediaType.ALL));return new ResponseEntity<>(body, status);}.............}

只要请求路径/error就可以进去到

errorHtml

这个方法，在浏览器请求http://localhost:8080/error就可以进入这个方法

解决方案

我这使用的springboot的版本为2.3.7.RELEASE

方案1：重写/error的请求

这种方案会直接舍弃掉HTML响应方式，但是前后端分离模式下，后端已经很少使用ModelAndView了

@Controllerpublic class NoFoundController extends AbstractErrorController {public NoFoundController(ErrorAttributes errorAttributes) {super(errorAttributes);}/*** 默认路径/error，可以通过server.error.path配置*/@RequestMapping(("${server.error.path:/error}"))public ResponseEntity<Map<String, Object>> notFoundError(HttpServletRequest request, HttpServletResponse response) {Map<String, Object> map = new HashMap<>(3);HttpStatus status = getStatus(request);map.put("code", status.value());map.put("data", null);map.put("message", status.toString());return new ResponseEntity<>(map, status);}/*** 在springboot2.3.0新增了server.error.path进行配置,这个废弃使用了，之前版本可以直接通过设置这个返回值修改默认/error的路径*/@Overridepublic String getErrorPath() {return null;}}

方案2：重写BasicErrorController中的错误处理

这种方式无法将HTML响应的也改成了json返回，请求中要有

"Accept": "application/json"

才能走json响应

@Controller@RequestMapping("${server.error.path:${error.path:/error}}")public class MyBasicErrorController extends BasicErrorController {public MyBasicErrorController(ServerProperties serverProperties) {// import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;super(new DefaultErrorAttributes(), serverProperties.getError());}/*** JSON响应*/@Overridepublic ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {Map<String, Object> map = new HashMap<>();HttpStatus status = getStatus(request);map.put("code", status.value());map.put("data", null);map.put("message", status.toString());return new ResponseEntity<>(map, status);}/*** HTML响应,根据需求处理自己处理*/@Overridepublic ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {return super.errorHtml(request, response);}}

其中

MyBasicErrorController

的构造函数可以参考spring自动装配

ErrorMvcAutoConfiguration

中的传值

//源码：public class ErrorMvcAutoConfiguration {private final ServerProperties serverProperties;public ErrorMvcAutoConfiguration(ServerProperties serverProperties) {this.serverProperties = serverProperties;}@Bean@ConditionalOnMissingBean(value = ErrorAttributes.class, search = SearchStrategy.CURRENT)public DefaultErrorAttributes errorAttributes() {// ErrorAttributesreturn new DefaultErrorAttributes();}@Bean@ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)public BasicErrorController basicErrorController(ErrorAttributes errorAttributes,ObjectProvider<ErrorViewResolver> errorViewResolvers) {// serverProperties.getErrorreturn new BasicErrorController(errorAttributes, this.serverProperties.getError(),errorViewResolvers.orderedStream().collect(Collectors.toList()));}........}

最后附上完整代码：

@Getterpublic class BusinessException extends RuntimeException {private Integer code;public BusinessException(Integer code, String message) {super(message);this.code = code;}public BusinessException(String message) {super(message);}}--------------------------------------------------------------------------------------------@ControllerAdvice@ResponseBody@Slf4jpublic class GlobalException {@ExceptionHandler(value = BusinessException.class)public ResponseModel<Void> businessExceptionError(BusinessException e) {log.error("业务异常", e);if (e.getCode() != null) {return ResponseModel.error(e.getCode(), e.getMessage());}return ResponseModel.error(e.getMessage());}@ExceptionHandler(value = Exception.class)public ResponseModel<Void> exceptionError(Exception e) {log.error("系统异常", e);return ResponseModel.error();}}--------------------------------------------------------------------------------------------@Getterpublic enum ResponseEnum {SUCCESS(0, "OK"),PARAMETER_ERROR(1,"参数异常"),NO_FOUND(404,"not found"),SYSTEM_ERROR(500, "服务器异常，请联系管理员");ResponseEnum(Integer code, String message) {this.code = code;this.message = message;}private final Integer code;private final String message;}--------------------------------------------------------------------------------------------public class ResponseModel<T> {private Integer code;private String message;private T data;public ResponseModel(Integer code, String message, T data) {this.code = code;this.message = message;this.data = data;}public static ResponseModel<Void> ok() {return ok(null);}public static <T> ResponseModel<T> ok(T data) {return new ResponseModel<>(ResponseEnum.SYSTEM_ERROR.getCode(), ResponseEnum.SYSTEM_ERROR.getMessage(), data);}public static <T> ResponseModel<T> ok(T data, String message) {return new ResponseModel<>(ResponseEnum.SYSTEM_ERROR.getCode(), message, data);}public static ResponseModel<Void> error(Integer statusCode, String message) {return new ResponseModel<>(statusCode, message, null);}public static ResponseModel<Void> error(String message) {return error(ResponseEnum.SYSTEM_ERROR.getCode(), message);}public static ResponseModel<Void> error() {return error(ResponseEnum.SYSTEM_ERROR.getCode(), ResponseEnum.SYSTEM_ERROR.getMessage());}}--------------------------------------------------------------------------------------------@Controllerpublic class NoFoundController extends AbstractErrorController {public NoFoundController(ErrorAttributes errorAttributes) {super(errorAttributes);}/*** 默认路径/error，可以通过server.error.path配置*/@RequestMapping(("${server.error.path:/error}"))public ResponseEntity<Map<String, Object>> notFoundError(HttpServletRequest request, HttpServletResponse response) {Map<String, Object> map = new HashMap<>(3);HttpStatus status = getStatus(request);map.put("code", status.value());map.put("data", null);map.put("message", status.toString());return new ResponseEntity<>(map, status);}/*** 在springboot2.3.0新增了server.error.path进行配置,这个废弃使用了，之前版本可以直接通过设置这个返回值修改默认/error的路径*/@Overridepublic String getErrorPath() {return null;}}

感谢各位小伙伴阅读到最后，如有错误，敬请指正。