这篇文章主要介绍了Spring注解@RestControllerAdvice原理解析,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
前言
前段时间部门搭建新系统，需要出异常后统一接口的返回格式，于是用到了Spring的注解@RestControllerAdvice。现在把此注解的用法总结一下。
用法
首先定义返回对象ResponseDto
package com.staff.points.common;import lombok.Data;import java.io.Serializable;@Datapublic class ResponseDto<T> implements Serializable { private static final long serialVersionUID = -284719732991678911L; private String code; private String message; private T data; public static <T> ResponseDto<T> assemblingSuccessResponse(T data) { ResponseDto<T> responseDto = new ResponseDto<>(); responseDto.setCode(ResponseCodeEnum.SUCCESS.getCode()); responseDto.setMessage(ResponseCodeEnum.SUCCESS.getMessage()); responseDto.setData(data); return responseDto; } public static <T> ResponseDto<T> assemblingSuccessResponse() { ResponseDto<T> responseDto = new ResponseDto<>(); responseDto.setCode(ResponseCodeEnum.SUCCESS.getCode()); responseDto.setMessage(ResponseCodeEnum.SUCCESS.getMessage()); responseDto.setData(null); return responseDto; } public static <T> ResponseDto<T> assemblingFailureResponse(ResponseCodeEnum data) { ResponseDto<T> responseDto = new ResponseDto<>(); responseDto.setCode(data.FAILURE.getCode()); responseDto.setMessage(data.FAILURE.getMessage()); return responseDto; } public static <T> ResponseDto<T> assemblingFailureResponse() { ResponseDto<T> responseDto = new ResponseDto<>(); responseDto.setCode(ResponseCodeEnum.FAILURE.getCode()); responseDto.setMessage(ResponseCodeEnum.FAILURE.getMessage()); return responseDto; }}
然后定义返回码的枚举类，此处只定义了两种，有需要可以往下添加很多。
package com.staff.points.common;import lombok.AllArgsConstructor;import lombok.Getter;@AllArgsConstructor@Getterpublic enum ResponseCodeEnum { SUCCESS("00", "成功"), FAILURE("01", "系统异常"); private String code; private String message;}
下面是自定义的异常类
package com.staff.points.common;import lombok.Data;@Datapublic class StaffPointsException extends RuntimeException{ private String code; private String message; public StaffPointsException () {} public StaffPointsException (Exception e) { super(e); } public StaffPointsException (String code, String message) { super(message); this.code = code; this.message = message; } public StaffPointsException (ResponseCodeEnum codeEnum) { super(codeEnum.getMessage()); this.code = codeEnum.getCode(); this.message = codeEnum.getMessage(); }}
然后是关键的@RestControllerAdvice修饰的类
package com.staff.points.exception;import com.staff.points.common.ResponseCodeEnum;import com.staff.points.common.ResponseDto;import com.staff.points.common.StaffPointsException;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Component;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.RestControllerAdvice;@RestControllerAdvice@Componentpublic class UnifyExceptionHandler { private Logger logger = LoggerFactory.getLogger(UnifyExceptionHandler.class); @ExceptionHandler(Exception.class) public ResponseDto handlerCommonException (Exception e) { ResponseDto responseDto = new ResponseDto<>(); responseDto.setCode(ResponseCodeEnum.FAILURE.getCode()); responseDto.setMessage(ResponseCodeEnum.FAILURE.getMessage()); logger.info("UnifyExceptionHandler.handlerCommonException exception:" + e); return responseDto; } // 报StaffPointException时，对其进行拦截并处理的方法 @ExceptionHandler(StaffPointsException.class) public ResponseDto handlerCustomizeException (StaffPointsException e) { ResponseDto responseDto = new ResponseDto<>(); responseDto.setCode(e.getCode()); responseDto.setMessage(e.getMessage()); logger.info("UnifyExceptionHandler.handlerCustomizeException StaffPointsException:" + e); return responseDto; }}
运行代码时，如果出现了StaffPointException，那么就会被拦截进入第27行的方法（就是说可以自由的在业务代码里往外throw自定义异常了）；如果出现了其他的异常，则进入18行的方法，统一返回。
验证一下，在代码里造一个NPE异常时，返回结果：
{ "code": "01", "message": "系统异常", "data": null }
造一个StaffPointsException异常时，返回结果：
{ "code": "99", "message": "自定义业务异常", "data": null }
它的作用原理，大体是先在spring初始化时将类扫描进容器，出异常后，在DispatcherServlet类的doDispatch方法中调用了对异常的拦截处理。
小结
看@RestControllerAdvice源码可以知道，它就是@ControllerAdvice和@ResponseBody的合并。此注解通过对异常的拦截实现的统一异常返回处理，如果大家在项目中有类似的需求，不妨试一下，好用又方便。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。
本文标题: Spring注解@RestControllerAdvice原理解析
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