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前言

项目中一般都会有规定好的接口返回格式,无论成功与失败,一般格式都是不变的,这样是为了方便前后端统一处理,今天就来说下前后端统一处理的较为优雅的方式;

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一、统一的返回格式

一般而言都会有一个统一的返回类作为接口的返回数据的封装,例如:

@Data
public class Result<T> implements Serializable {private int code = HttpStatus.OK.value();private String msg;private T data;public static <T> Result<T> success() {return success(null);}public static <T> Result<T> failure() {return failure(HttpStatus.BAD_REQUEST.value(),HttpStatus.BAD_REQUEST.getReasonPhrase());}public static <T> Result<T> success(T data) {return new Result<T>(HttpStatus.OK.value(), HttpStatus.OK.getReasonPhrase(), data);}public static <T> Result<T> failure(int errorCode, String errorMsg) {return failure(errorCode, errorMsg, null);}public static <T> Result<T> failure(int code, String errorMsg, T data) {return new Result<T>(code, errorMsg, data);}public Result(int code, String msg, T data) {this.code = code;this.msg = msg;this.data = data;}}

然后我们通过此类作为返回参数的统一封装,这样无论成功与否,都是三个参数
code msg data

二、全局异常处理

• 项目中难免会有异常抛出
  1. 服务端报错的异常
  2. 处理逻辑中的异常(参数校验, 逻辑不通等)
• 由于我们一般都是前后端分离项目,所以都是接口方式的返回,那么我们只需要处理接口就可以了

@RestControllerAdvice
@Slf4j
public class ControllerExceptionHandel {@ExceptionHandler(ValidationException.class)public Result<String> handleException(ValidationException e) {e.printStackTrace();log.error("参数校验发生异常:{}", e.getMessage());return Result.failure(HttpStatus.BAD_REQUEST.value(), e.getMessage());}@ExceptionHandler(value = NullPointerException.class)public Result<String> exceptionHandler(NullPointerException e) {e.printStackTrace();log.error("空指针异常:{}", e.getMessage());return Result.failure(HttpStatus.INTERNAL_SERVER_ERROR.value(), e.getMessage());}@ExceptionHandler(value = {Exception.class, RuntimeException.class})public Result<String> exceptionHandler(Exception e) {e.printStackTrace();log.error("运行时发生异常:{}", e.getMessage());return Result.failure(HttpStatus.INTERNAL_SERVER_ERROR.value(), e.getMessage());}@ExceptionHandler(AsyncRequestTimeoutException.class)public Result<String> handException(AsyncRequestTimeoutException e) {e.printStackTrace();log.error("运行时超时异常:{}", e.getMessage());return Result.failure(HttpStatus.BAD_REQUEST.value(), e.getMessage());}
}

一般来说控制器可以这样用

@RestController
@RequestMapping("lang")
public class LangController {@RequestMapping("get")public Result get(){return Result.success(LocalUtil.get("demo"));}
}

三、全局返回处理(装逼用的)

还是上面的全局异常处理,不过要增加点东西

• 实现ResponseBodyAdvice接口
• 实现两个方法
  完整代码如下:

@RestControllerAdvice
@Slf4j
public class ControllerExceptionHandel implements ResponseBodyAdvice<Object>{@Autowiredprivate ObjectMapper objectMapper;@ExceptionHandler(ValidationException.class)public Result<String> handleException(ValidationException e) {e.printStackTrace();log.error("参数校验发生异常:{}", e.getMessage());return Result.failure(HttpStatus.BAD_REQUEST.value(), e.getMessage());}@ExceptionHandler(value = NullPointerException.class)public Result<String> exceptionHandler(NullPointerException e) {e.printStackTrace();log.error("空指针异常:{}", e.getMessage());return Result.failure(HttpStatus.INTERNAL_SERVER_ERROR.value(), e.getMessage());}@ExceptionHandler(value = {Exception.class, RuntimeException.class})public Result<String> exceptionHandler(Exception e) {e.printStackTrace();log.error("运行时发生异常:{}", e.getMessage());return Result.failure(HttpStatus.INTERNAL_SERVER_ERROR.value(), e.getMessage());}@ExceptionHandler(AsyncRequestTimeoutException.class)public Result<String> handException(AsyncRequestTimeoutException e) {e.printStackTrace();log.error("运行时超时异常:{}", e.getMessage());return Result.failure(HttpStatus.BAD_REQUEST.value(), e.getMessage());}@Overridepublic boolean supports(MethodParameter returnType, Class converterType) {return true;}@SneakyThrows@Overridepublic Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {Class<?> returnClass = returnType.getMethod().getReturnType();if (body instanceof String || Objects.equals(returnClass, String.class)) {return objectMapper.writeValueAsString(Result.success(body));}if (body instanceof Result) {return body;}return Result.success(body);}
}

这样控制器中既可以像之前那样使用,还可以像如下使用
它会自动封装返回结果,无需手动封装

@RestController
@RequestMapping("lang")
public class LangController {@RequestMapping("get")public String get(){return LocalUtil.get("demo");}
}

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总结

如果项目中按照这种方式 @RestControllerAdvice + ResponseBodyAdvice接口,就能实现大部分的统一返回出参功能了,无论是正常请求还是异常请求,无论是简单类型还是集合返回,相当于都有了统一的封装处理;
快试试,用到项目中吧~