Spring中@RestControllerAdvice注解的原理是什么,针对这个问题,这篇文章详细介绍了相对应的分析和解答,希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。
首先定义返回对象ResponseDto
package com.staff.points.common;
import lombok.Data;
import java.io.Serializable;
@Data
public 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
@Getter
public 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;
@Data
public 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
@Component
public 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。
。
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