SpringBoot构建电商基础秒杀项目 学习笔记
定义通用的返回对象
public class CommonReturnType {
// success, fail
private String status;
// status = success, data 内返回前端需要的 json数据
// status = fail, data 内使用通用的错误码格式
private Object data;
public static CommonReturnType create(Object result){
return create(result, "success");
}
public static CommonReturnType create(Object result, String status){
CommonReturnType type = new CommonReturnType();
type.setStatus(status);
type.setData(result);
return type;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
定义错误接口
public interface CommonError {
public int getErrCode();
public String getErrMsg();
public CommonError setErrMsg(String errMsg);
}
定义错误类型枚举
public enum EmBusinessError implements CommonError {
// 通用错误类型 10001
PARAMETER_VALIDATION_ERROR(10001, "参数不合法"),
UNKNOWN_ERROR(10002, "未知错误"),
// 20000 开头为用户信息相关错误定义
USER_NOT_EXIST(20001, "用户不存在"),
;
private int errCode;
private String errMsg;
private EmBusinessError(int errCode, String errMsg){
this.errCode = errCode;
this.errMsg = errMsg;
}
@Override
public int getErrCode() {
return this.errCode;
}
@Override
public String getErrMsg() {
return this.errMsg;
}
@Override
public CommonError setErrMsg(String errMsg) {
this.errMsg = errMsg;
return this;
}
}
包装器业务异常类实现
// 包装器业务异常类实现
public class BusinessException extends Exception implements CommonError {
private CommonError commonError;
public BusinessException(CommonError commonError){
super();
this.commonError = commonError;
}
public BusinessException(CommonError commonError, String errMsg){
super();
this.commonError = commonError;
this.commonError.setErrMsg(errMsg);
}
@Override
public int getErrCode() {
return this.commonError.getErrCode();
}
@Override
public String getErrMsg() {
return this.commonError.getErrMsg();
}
@Override
public CommonError setErrMsg(String errMsg) {
this.commonError.setErrMsg(errMsg);
return this;
}
}
定义 BaseController 处理异常
public class BaseController {
// 定义 exceptionhandler 解决未被 controller 层吸收的 exception
@ExceptionHandler(Exception.class)
@ResponseStatus(HttpStatus.OK)
@ResponseBody
public Object handlerException(HttpServletRequest request, Exception ex){
Map<String, Object> responseData = new HashMap<>();
if(ex instanceof BusinessException){
BusinessException businessException = (BusinessException)ex;
responseData.put("errCode", businessException.getErrCode());
responseData.put("errMsg", businessException.getErrMsg());
}else{
responseData.put("errCode", EmBusinessError.UNKNOWN_ERROR.getErrCode());
responseData.put("errMsg", EmBusinessError.UNKNOWN_ERROR.getErrMsg());
}
return CommonReturnType.create(responseData, "fail");
}
}
修改 UserController
@Controller("user")
@RequestMapping("/user")
public class UserController extends BaseController{
@Autowired
private UserService userService;
@RequestMapping("/get")
@ResponseBody
public CommonReturnType getUser(@RequestParam(name="id") Integer id) throws BusinessException{
UserModel userModel = userService.getUserById(id);
if(userModel == null){
// userModel.setEncrptPassword("123");
throw new BusinessException(EmBusinessError.USER_NOT_EXIST);
}
UserVO userVO = convertFromModel(userModel);
return CommonReturnType.create(userVO);
}
private UserVO convertFromModel(UserModel userModel){
if(userModel == null){
return null;
}
UserVO userVO = new UserVO();
BeanUtils.copyProperties(userModel, userVO);
return userVO;
}
}