知识碎片-SpringBoot统一返回结果和捕获异常

统一返回结果

1. 定义统一返回结果类ResultResponse
2. 定义新注解@ResponseResult来标记需要拦截的方法或类
3. 添加RestControllerAdvice注解，实现ResponseBodyAdvice接口，重写support, beforeBodyWrite方法

统一结果类ResultResponse

@Setter
@Getter
public class ResultResponse<T> {/*** 响应代码*/private String code;/*** 响应消息*/private String message;/*** 响应结果*/private T result;public ResultResponse() {}public ResultResponse(BaseErrorInfoInterface errorInfo) {this.code = errorInfo.getResultCode();this.message = errorInfo.getResultMsg();}/*** 成功*/public static <T> ResultResponse<T> success() {return success(null);}/*** 成功*/public static <T> ResultResponse<T> success(T data) {ResultResponse<T> rb = new ResultResponse<>();rb.setCode(ExceptionEnum.SUCCESS.getResultCode());rb.setMessage(ExceptionEnum.SUCCESS.getResultMsg());rb.setResult(data);return rb;}/*** 失败*/public static <T> ResultResponse<T> error(BaseErrorInfoInterface errorInfo) {ResultResponse<T> rb = new ResultResponse<>();rb.setCode(errorInfo.getResultCode());rb.setMessage(errorInfo.getResultMsg());rb.setResult(null);return rb;}/*** 失败*/public static <T> ResultResponse<T> error(String code, String message) {ResultResponse<T> rb = new ResultResponse<>();rb.setCode(code);rb.setMessage(message);rb.setResult(null);return rb;}/*** 失败*/public static <T> ResultResponse<T> error(String message) {ResultResponse<T> rb = new ResultResponse<>();rb.setCode("-1");rb.setMessage(message);rb.setResult(null);return rb;}@Overridepublic String toString() {return JSONObject.toJSONString(this);}}

定义新注解ResponseResult

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
@Documented
public @interface ResponseResult {
}

ResponseResultBodyAdvice类

1. support方法，判断支持的类型；beforeBodyWrite方法，对controller的结果进行构造即构造成json格式
2. RestControllerAdvice注解=ResponseBody+ControllerAdvice

@RestControllerAdvice
@Slf4j
public class ResponseResultBodyAdvice implements ResponseBodyAdvice<Object> {@Resourceprivate ObjectMapper objectMapper;private static final Class<? extends Annotation> ANNOTATION_TYPE = ResponseResult.class;@Overridepublic boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {return AnnotatedElementUtils.hasAnnotation(returnType.getContainingClass(), ANNOTATION_TYPE) || returnType.hasMethodAnnotation(ANNOTATION_TYPE);}@SneakyThrows@Overridepublic Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {// 如果返回类型是string，那么springmvc是直接返回的，此时需要手动转化为jsonClass<?> returnClass = returnType.getMethod().getReturnType();if (body instanceof String || Objects.equals(returnClass, String.class)) {return objectMapper.writeValueAsString(ResultResponse.success(body));}// 防止重复包裹的问题出现if (body instanceof ResultResponse) {return body;}return ResultResponse.success(body);}
}

统一捕获异常

@ExceptionHandler(value = BizException.class) 捕获自定义异常

@ControllerAdvice
public class GlobalExceptionHandler {private static final Logger logger = LoggerFactory.getLogger(GlobalExceptionHandler.class);/*** 处理自定义的业务异常** @param req* @param e* @return*/@ExceptionHandler(value = BizException.class)@ResponseBodypublic ResultResponse<Void> bizExceptionHandler(HttpServletRequest req, BizException e) {logger.error("发生业务异常！原因是：{}", e.getErrorMsg());return ResultResponse.error(e.getErrorCode(), e.getErrorMsg());}/*** 处理空指针的异常** @param req* @param e* @return*/@ExceptionHandler(value = NullPointerException.class)@ResponseBodypublic ResultResponse<Void> exceptionHandler(HttpServletRequest req, NullPointerException e) {logger.error("发生空指针异常！原因是:", e);return ResultResponse.error(ExceptionEnum.BODY_NOT_MATCH);}/*** 处理其他异常** @param req* @param e* @return*/@ExceptionHandler(value = Exception.class)@ResponseBodypublic ResultResponse<Void> exceptionHandler(HttpServletRequest req, Exception e) {logger.error("未知异常！原因是:", e);return ResultResponse.error(ExceptionEnum.INTERNAL_SERVER_ERROR);}
}