项目训练营第五天

后端代码优化

通用异常处理类编写

@Data
public class BaseResponse<T> implements Serializable {int code;T data;String message = null;String description = null;public BaseResponse(int code, T data, String message, String description) {this.code = code;this.data = data;this.message = message;this.description = description;}public BaseResponse(int code, T data, String message) {this.code = code;this.data = data;this.message = message;this.description = "";}public BaseResponse(int code, T data) {this.code = code;this.data = data;this.message = "";this.description = "";}
}

将之前UserController中各函数的返回值改成泛型BaseResponse对象，便于对原本的返回值进行封装，采用装饰者模式在其外围加上一些参数。

工具类ResultUtils的编写

为了便于修改和返回BaseResponse对象，编写以下ResultUtils函数，对成功和失败的情况进行统一处理

public class ResultUtils {/*** 工具类* @param data* @return* @author yuxin*/public static <T> BaseResponse<T> success(T data) {return new BaseResponse<T>(0, data, "ok");}public  static <T> BaseResponse<T> error(ErrorCode e) {return new BaseResponse<T>(e.getCode(), (T)"", e.getMessage(), e.getDescription());}public  static BaseResponse error(int code, String message, String description) {return new BaseResponse(code, message, description);}
}

枚举值ErrorCode类编写

为了方便对原本的参数值进行封装，编写一个枚举类记录各种常见的错误异常类型

public enum ErrorCode {PARAMS_ERROR(400000, "请求参数错误", ""),PARAMS_NULL(400001, "请求参数为空", ""),NOT_LOGIN(40100,"未登录",""),NO_AUTH(40101, "无权限", ""),SYSTEM_ERROR(50000, "系统内部异常", "");private final int code;private final String message;private final String description;ErrorCode(int code, String message, String description) {this.code = code;this.message = message;this.description = description;}public int getCode() {return code;}public String getMessage() {return message;}public String getDescription() {return description;}
}

• 三个类分别写在对应名称的类中，放在一个common的文件夹下
• 测试结果如图：
  

业务异常类编写

@Data
public class BusinessException extends RuntimeException {private int code;private String description;public BusinessException(int code, String description) {this.code = code;this.description = description;}public BusinessException(String message, int code, String description) {super(message);this.code = code;this.description = description;}public BusinessException(String message, Throwable cause, int code, String description) {super(message, cause);this.code = code;this.description = description;}public BusinessException(Throwable cause, int code, String description) {super(cause);this.code = code;this.description = description;}public BusinessException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace, int code, String description) {super(message, cause, enableSuppression, writableStackTrace);this.code = code;this.description = description;}
}

全局异常处理类编写

通过编写全局异常处理类，将内部异常进行封装，不返回给前端代码关于代码结构的异常信息。

@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {@ExceptionHandler(BusinessException.class)public BaseResponse BusinessExceptionHandler(BusinessException e) {return ResultUtils.error(e.getCode(), e.getMessage(), "");}@ExceptionHandler(RuntimeException.class)public BaseResponse RuntimeExceptionHandler(RuntimeException e) {return ResultUtils.error(ErrorCode.SYSTEM_ERROR.getCode(), ErrorCode.SYSTEM_ERROR.getMessage(), "");}}

控制层优化

• 用户查询、删除优化

将原本判断是否为管理员的语句封装，放到业务层中写成一个函数isAdmin

    public boolean isAdmin(HttpServletRequest request) {Object userObj = request.getSession().getAttribute(USER_LOGIN_STATE);User user = (User)userObj;if (user == null || user.getUserRole() != 1) {return false;}return true;}