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

@RestController
public 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 Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Wed Dec 29 10:14:36 CST 2021

There 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 {

...........

@Override
public 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
@RequestMapping
public 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

@Controller
public 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
*/
@Override
public 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
*/
@Override
public 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
*/
@Override
public 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() {
// ErrorAttributes
return new DefaultErrorAttributes();
}

@Bean
@ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)
public BasicErrorController basicErrorController(ErrorAttributes errorAttributes,
ObjectProvider<ErrorViewResolver> errorViewResolvers) {
// serverProperties.getError
return new BasicErrorController(errorAttributes, this.serverProperties.getError(),
errorViewResolvers.orderedStream().collect(Collectors.toList()));
}
........
}

最后附上完整代码：

@Getter
public 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
@Slf4j
public 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();
}
}
--------------------------------------------------------------------------------------------
@Getter
public 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());
}
}
--------------------------------------------------------------------------------------------
@Controller
public 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
*/
@Override
public String getErrorPath() {
return null;
}
}

感谢各位小伙伴阅读到最后，如有错误，敬请指正。