在 Spring Boot 中,可以通过使用 @ControllerAdvice
注解和 @ExceptionHandler
注解来实现全局异常拦截。
@RestControllerAdvice
@RestControllerAdvice
是 Spring Framework 提供的注解,用于定义全局异常处理类,并且结合 @ExceptionHandler
注解来处理异常。与 @ControllerAdvice
不同的是,@RestControllerAdvice
默认情况下会将返回值转换为 JSON 格式。
@RestControllerAdvice
public class GlobalExceptionHandler {//.....拦截异常方法}
@ResponseStatus(...)
@ResponseStatus(HttpStatus.BAD_REQUEST)
是一个注解,用于在异常处理方法上指定特定的HTTP状态码。当该异常被抛出时,将返回指定的HTTP状态码给客户端。
@RestControllerAdvice
public class GlobalExceptionHandler {//.....拦截异常方法/*** 缺少请求体异常处理器* @param e 缺少请求体异常 使用get方式请求 而实体使用@RequestBody修饰*/@ResponseStatus(HttpStatus.BAD_REQUEST)public ResponseResult parameterBodyMissingExceptionHandler(HttpMessageNotReadableException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',请求体缺失'{}'", requestURI, e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), sysError);}
}
@ExceptionHandler(...)
@ExceptionHandler(...)
是一个异常处理注解,用于捕获请求的异常。当客户端发送的请求消息无法被框架正确解析时,将抛出该异常并调用对应的异常处理方法。
@RestControllerAdvice
public class GlobalExceptionHandler {//.....拦截异常方法/*** 缺少请求体异常处理器* @param e 缺少请求体异常 使用get方式请求 而实体使用@RequestBody修饰*/@ResponseStatus(HttpStatus.BAD_REQUEST)@ExceptionHandler(HttpMessageNotReadableException.class)public ResponseResult parameterBodyMissingExceptionHandler(HttpMessageNotReadableException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',请求体缺失'{}'", requestURI, e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), sysError);}
}
RuntimeException
RuntimeException
是 Java 提供的一个运行时异常类。与受检查异常不同,运行时异常不需要在方法声明中显式地声明或捕获,并且在运行时抛出时也不需要强制捕获或处理。所以我们可以在全局异常捕获中去捕获这个异常
public class BusinessException extends RuntimeException {private int code;//使用枚举构造public BusinessException(HttpCodeEnum httpCodeEnum){super(httpCodeEnum.getMsg());this.code=httpCodeEnum.getCode();}//使用自定义消息体public BusinessException(HttpCodeEnum httpCodeEnum, String msg){super(msg);this.code=httpCodeEnum.getCode();}//根据异常构造public BusinessException(HttpCodeEnum httpCodeEnum, Throwable msg){super(msg);this.code=httpCodeEnum.getCode();}}
上述代码定义了一个名为 BusinessException
的自定义异常类,它继承自 RuntimeException
。
这个自定义异常类具有以下特点:
- 包含了一个
code
字段,用于表示异常的错误码。 - 提供了不同的构造方法,以方便在抛出异常时指定错误码和错误信息。
BusinessException(HttpCodeEnum httpCodeEnum)
构造方法使用枚举类型HttpCodeEnum
来设置异常的错误码和错误信息。BusinessException(HttpCodeEnum httpCodeEnum, String msg)
构造方法使用自定义的错误信息来设置异常的错误码和错误信息。BusinessException(HttpCodeEnum httpCodeEnum, Throwable msg)
构造方法使用其他异常的实例来设置异常的错误码,并可选地提供通过Throwable
获取的错误信息。
HttpCodeEnum
枚举类
我们还需要一个类表示 HTTP 响应的状态码和对应的消息 ,以下为基本的举例查考。
public enum HttpCodeEnum {// 成功SUCCESS(200, "操作成功"),// 登录NEED_LOGIN(401, "需要登录后操作"),NO_OPERATOR_AUTH(403, "无权限操作"),SYSTEM_ERROR(500, "出现错误"),USERNAME_EXIST(501, "用户名已存在"),PHONENUMBER_EXIST(502, "手机号已存在"), EMAIL_EXIST(503, "邮箱已存在"),REQUIRE_USERNAME(504, "必需填写用户名"),CONTENT_NOT_NULL(506, "评论内容不能为空"),FILE_TYPE_ERROR(507, "文件类型错误"),USERNAME_NOT_NULL(508, "用户名不能为空"),NICKNAME_NOT_NULL(509, "昵称不能为空"),PASSWORD_NOT_NULL(510, "密码不能为空"),EMAIL_NOT_NULL(511, "邮箱不能为空"),NICKNAME_EXIST(512, "昵称已存在"),LOGIN_ERROR(505, "用户名或密码错误");int code;String msg;HttpCodeEnum(int code, String errorMessage) {this.code = code;this.msg = errorMessage;}public int getCode() {return code;}public String getMsg() {return msg;}
}
上述代码定义了一个 HttpCodeEnum
枚举类,用于表示 HTTP 响应的状态码和对应的消息。
这个枚举类具有以下特点:
- 包含一组枚举常量,每个常量代表一个 HTTP 响应状态。
- 每个常量都有一个整型的
code
和一个字符串类型的msg
,分别表示状态码和对应的消息。 - 提供了相应的构造方法、获取
code
和msg
的方法。
ResponseResult类
该类的主要作用是封装接口返回的数据,统一格式化输出,方便前端调用和展示。
import lombok.Data;import java.io.Serializable;
@Data
public class ResponseResult<T> implements Serializable {private Boolean success;private Integer code;private String msg;private T data;public ResponseResult() {this.success=true;this.code = HttpCodeEnum.SUCCESS.getCode();this.msg = HttpCodeEnum.SUCCESS.getMsg();}public ResponseResult(Integer code, T data) {this.code = code;this.data = data;}public ResponseResult(Integer code, String msg, T data) {this.code = code;this.msg = msg;this.data = data;}public ResponseResult(Integer code, String msg) {this.code = code;this.msg = msg;}public static ResponseResult errorResult(int code, String msg) {ResponseResult result = new ResponseResult();return result.error(code, msg);}public static ResponseResult okResult() {ResponseResult result = new ResponseResult();return result;}public static ResponseResult okResult(int code, String msg) {ResponseResult result = new ResponseResult();return result.ok(code, null, msg);}public static ResponseResult setHttpCodeEnum(HttpCodeEnum enums) {return okResult(enums.getCode(), enums.getMsg());}public ResponseResult<?> error(Integer code, String msg) {this.success=false;this.code = code;this.msg = msg;return this;}public ResponseResult<?> ok(Integer code, T data) {this.success=true;this.code = code;this.data = data;return this;}public ResponseResult<?> ok(Integer code, T data, String msg) {this.success=true;this.code = code;this.data = data;this.msg = msg;return this;}public ResponseResult<?> ok(T data) {this.success=true;this.data = data;return this;}}
全局异常捕获
全局异常捕获是一种处理应用程序中未处理的异常的机制,它可以统一处理应用程序中的异常,避免异常导致程序崩溃或向用户显示不友好的错误信息。我们可以通过上述的解释去捕获异常,定义code类型枚举返回ResponseResult给前端
import com.example.demo.util.HttpCodeEnum;
import com.example.demo.util.ResponseResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.util.CollectionUtils;
import org.springframework.validation.FieldError;
import org.springframework.validation.ObjectError;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestControllerAdvice;import javax.servlet.http.HttpServletRequest;
import java.util.List;@RestControllerAdvice
public class GlobalExceptionHandler {private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);@Autowiredprivate HttpServletRequest httpServletRequest;private final String sysError="系统出错";/*** 缺少请求体异常处理器* @param e 缺少请求体异常 使用get方式请求 而实体使用@RequestBody修饰*/@ResponseStatus(HttpStatus.BAD_REQUEST)@ExceptionHandler(HttpMessageNotReadableException.class)public ResponseResult parameterBodyMissingExceptionHandler(HttpMessageNotReadableException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',请求体缺失'{}'", requestURI, e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), sysError);}/** @Description: 捕获请求方法异常,比如post接口使用了get*/@ResponseStatus(HttpStatus.METHOD_NOT_ALLOWED)@ExceptionHandler(HttpRequestMethodNotSupportedException.class)public ResponseResult methodNotAllowedHandler(HttpRequestMethodNotSupportedException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',请求方法不被允许'{}'", requestURI, e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), sysError);}// get请求的对象参数校验异常@ResponseStatus(HttpStatus.BAD_REQUEST)@ExceptionHandler({MissingServletRequestParameterException.class})public ResponseResult bindExceptionHandler(MissingServletRequestParameterException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',get方式请求参数'{}'必传", requestURI, e.getParameterName());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), sysError);}// post请求的对象参数校验异常@ResponseStatus(HttpStatus.BAD_REQUEST)@ExceptionHandler({MethodArgumentNotValidException.class})public ResponseResult methodArgumentNotValidHandler(MethodArgumentNotValidException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',post方式请求参数异常'{}'", requestURI, e.getMessage());List<ObjectError> allErrors = e.getBindingResult().getAllErrors();return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), getValidExceptionMsg(allErrors));}// 业务类异常@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)@ExceptionHandler(BusinessException.class)public ResponseResult businessExceptionHandler(BusinessException e) {String requestURI = httpServletRequest.getRequestURI();System.out.println(e);log.error("请求地址'{}',捕获业务类异常'{}'", requestURI,e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), e.getMessage());}// 运行时异常@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)@ExceptionHandler(RuntimeException.class)public ResponseResult runtimeExceptionHandler(RuntimeException e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',捕获运行时异常'{}'", requestURI, e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), e.getMessage());}// 系统级别异常@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)@ExceptionHandler(Throwable.class)public ResponseResult throwableExceptionHandler(Throwable e) {String requestURI = httpServletRequest.getRequestURI();log.error("请求地址'{}',捕获系统级别异常'{}'", requestURI,e.getMessage());return ResponseResult.errorResult(HttpCodeEnum.SYSTEM_ERROR.getCode(), e.getMessage());}private String getValidExceptionMsg(List<ObjectError> errors) {if(!CollectionUtils.isEmpty(errors)){StringBuilder sb = new StringBuilder();errors.forEach(error -> {if (error instanceof FieldError) {sb.append(((FieldError)error).getField()).append(":");}sb.append(error.getDefaultMessage()).append(";");});String msg = sb.toString();msg = msg.substring(0, msg.length() -1);return msg;}return null;}}
测试
入参不正确时
发出请求
返回结果
捕获异常
运行时错误
发起请求
返回结果
捕获异常
业务异常
发送请求
返回结果
捕获异常