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

demo:创建一个自定义BaseException 异常，可以根据需要自定义各种异常

package com.ruoyi.common.exception;import com.ruoyi.common.utils.MessageUtils;
import com.ruoyi.common.utils.StringUtils;/*** 基础异常* * @author ruoyi*/
public class BaseException extends RuntimeException
{private static final long serialVersionUID = 1L;/*** 所属模块*/private String module;/*** 错误码*/private String code;/*** 错误码对应的参数*/private Object[] args;/*** 错误消息*/private String defaultMessage;public BaseException(String module, String code, Object[] args, String defaultMessage){this.module = module;this.code = code;this.args = args;this.defaultMessage = defaultMessage;}public BaseException(String module, String code, Object[] args){this(module, code, args, null);}public BaseException(String module, String defaultMessage){this(module, null, null, defaultMessage);}public BaseException(String code, Object[] args){this(null, code, args, null);}public BaseException(String defaultMessage){this(null, null, null, defaultMessage);}@Overridepublic String getMessage(){String message = null;if (!StringUtils.isEmpty(code)){message = MessageUtils.message(code, args);}if (message == null){message = defaultMessage;}return message;}public String getModule(){return module;}public String getCode(){return code;}public Object[] getArgs(){return args;}public String getDefaultMessage(){return defaultMessage;}
}

新建一个全局异常处理类：加上@RestControllerAdvice注解，每个异常方法需要加上@ExceptionHandler(BaseException.class)注解

package com.ruoyi.framework.web.exception;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.authentication.AccountExpiredException;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.validation.BindException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.NoHandlerFoundException;
import com.ruoyi.common.constant.HttpStatus;
import com.ruoyi.common.exception.BaseException;
import com.ruoyi.common.exception.CustomException;
import com.ruoyi.common.exception.DemoModeException;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.framework.web.domain.AjaxResult;/*** 全局异常处理器* * @author */
@RestControllerAdvice
public class GlobalExceptionHandler
{private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);/*** 基础异常*/@ExceptionHandler(BaseException.class)public AjaxResult baseException(BaseException e){return AjaxResult.error(e.getMessage());}/*** 业务异常*/@ExceptionHandler(CustomException.class)public AjaxResult businessException(CustomException e){if (StringUtils.isNull(e.getCode())){return AjaxResult.error(e.getMessage());}return AjaxResult.error(e.getCode(), e.getMessage());}@ExceptionHandler(NoHandlerFoundException.class)public AjaxResult handlerNoFoundException(Exception e){log.error(e.getMessage(), e);return AjaxResult.error(HttpStatus.NOT_FOUND, "路径不存在，请检查路径是否正确");}@ExceptionHandler(AccessDeniedException.class)public AjaxResult handleAuthorizationException(AccessDeniedException e){log.error(e.getMessage());return AjaxResult.error(HttpStatus.FORBIDDEN, "没有权限，请联系管理员授权");}@ExceptionHandler(AccountExpiredException.class)public AjaxResult handleAccountExpiredException(AccountExpiredException e){log.error(e.getMessage(), e);return AjaxResult.error(e.getMessage());}@ExceptionHandler(UsernameNotFoundException.class)public AjaxResult handleUsernameNotFoundException(UsernameNotFoundException e){log.error(e.getMessage(), e);return AjaxResult.error(e.getMessage());}@ExceptionHandler(Exception.class)public AjaxResult handleException(Exception e){log.error(e.getMessage(), e);return AjaxResult.error(e.getMessage());}/*** 自定义验证异常*/@ExceptionHandler(BindException.class)public AjaxResult validatedBindException(BindException e){log.error(e.getMessage(), e);String message = e.getAllErrors().get(0).getDefaultMessage();return AjaxResult.error(message);}/*** 自定义验证异常*/@ExceptionHandler(MethodArgumentNotValidException.class)public Object validExceptionHandler(MethodArgumentNotValidException e){log.error(e.getMessage(), e);String message = e.getBindingResult().getFieldError().getDefaultMessage();return AjaxResult.error(message);}/*** 演示模式异常*/@ExceptionHandler(DemoModeException.class)public AjaxResult demoModeException(DemoModeException e){return AjaxResult.error("演示模式，不允许操作");}
}

在业务方法抛出异常：

 @Overridepublic UserDetails loadUserByUsername(String username) throws UsernameNotFoundException{SysUser user = userService.selectUserByUserName(username);if (StringUtils.isNull(user)){log.info("登录用户：{} 不存在.", username);throw new UsernameNotFoundException("登录用户：" + username + " 不存在");}else if (UserStatus.DELETED.getCode().equals(user.getDelFlag())){log.info("登录用户：{} 已被删除.", username);throw new BaseException("对不起，您的账号：" + username + " 已被删除");}else if (UserStatus.DISABLE.getCode().equals(user.getStatus())){log.info("登录用户：{} 已被停用.", username);throw new BaseException("对不起，您的账号：" + username + " 已停用");}return createLoginUser(user);}

AjaxResult的构造方法

/*** 返回错误消息* * @param msg 返回内容* @return 警告消息*/public static AjaxResult error(String msg){return AjaxResult.error(msg, null);}
/*** 返回错误消息* * @param msg 返回内容* @param data 数据对象* @return 警告消息*/public static AjaxResult error(String msg, Object data){return new AjaxResult(HttpStatus.ERROR, msg, data);}

这样我们就可以自定义各种异常，在业务代码中不进行处理便可抛出异常进行中止程序，统一返回自定义的异常json格式