# 具体遇到的问题
首先，按照老师的步骤把用户和公共模块整合到了一起，没有异常的用户模块已经测试成功。但是用Postman测试注册相同用户名，没有提示，只有500错误的提示。

现在已知，从Controller中直接返回的ApiResponse对象没有问题

return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_USER_NAME);

可以正常显示“没有用户名”等异常

但是从Service中

throw new ImoocMallException(ImoocMallExceptionEnum.NAME_EXIST);

就会出现所说的问题，最终响应500错误

断点打在GlobalExceptionHander拦截ImoocMallException的方法内部，发现根本没有进入该方法的执行

@ExceptionHandler(ImoocMallException.class)
@ResponseBody
public ApiRestResponse handleImoocMallException(ImoocMallException e) {
//打印日志
    log.error("ImoocMallException: " + e);
    //拦截到异常后返回Response信息
    return ApiRestResponse.error(e.getCode(), e.getMsg());
}

# 报错信息的截图

{

"timestamp": "2020-11-18T09:12:04.301+0000",

"status": 500,

"error": "Internal Server Error",

"message": "No message available",

"path": "/register"

}

# 相关课程内容截图

# 尝试过的解决思路和结果

# 粘贴全部相关代码，切记添加代码注释（请勿截图）

package com.example.cloud.mall.exception;


import com.example.cloud.mall.common.ApiRestResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.ArrayList;
import java.util.List;

//统一异常处理类
@ControllerAdvice
public class GlobalExceptionHandler {
private final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);

    @ExceptionHandler(Exception.class)
@ResponseBody
    public ApiRestResponse handleException(Exception e) {
log.error("Default Exception: " + e);
        return ApiRestResponse.error(ImoocMallExceptionEnum.SYSTEM_ERROR);
    }

//拦截ImoocMallException异常
    @ExceptionHandler(ImoocMallException.class)
@ResponseBody
    public ApiRestResponse handleImoocMallException(ImoocMallException e) {
//打印日志
        log.error("ImoocMallException: " + e);
        //拦截到异常后返回Response信息
        return ApiRestResponse.error(e.getCode(), e.getMsg());
    }

//对于Valid参数校验失败后的异常处理
    @ExceptionHandler(MethodArgumentNotValidException.class)
@ResponseBody
    public ApiRestResponse handleMethodArgumentNotValidException(MethodArgumentNotValidException e) {
log.error("MethodArgumentNotValidException: " + e);
        return handleBindingResult(e.getBindingResult());
    }

private ApiRestResponse handleBindingResult(BindingResult bindingResult) {
//把异常处理为对外暴露的提示
        List<String> list = new ArrayList<>();
        if (bindingResult.hasErrors()) {
            List<ObjectError> allErrors = bindingResult.getAllErrors();
            for (ObjectError objectError : allErrors) {
                String defaultMessage = objectError.getDefaultMessage();
                list.add(defaultMessage);
            }
        }
if (list.size() == 0) {
return ApiRestResponse.error(ImoocMallExceptionEnum.REQUEST_PARAM_ERROR);
        }
return ApiRestResponse.error(ImoocMallExceptionEnum.REQUEST_PARAM_ERROR.getCode(), list.toString());
    }

}

package com.example.cloud.mall.user.service.impl;

import com.example.cloud.mall.exception.ImoocMallException;
import com.example.cloud.mall.exception.ImoocMallExceptionEnum;
import com.example.cloud.mall.user.model.dao.UserMapper;
import com.example.cloud.mall.user.model.pojo.User;
import com.example.cloud.mall.user.service.UserService;
import com.example.cloud.mall.util.MD5Utils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.security.NoSuchAlgorithmException;

@Service("userService")
public class UserServiceImpl implements UserService {
@Autowired
    UserMapper userMapper;

    @Override
    public void register(String username, String password) throws ImoocMallException, NoSuchAlgorithmException {
//检验是否有重名
        User user = userMapper.selectByName(username);
        if (user != null) {
throw new ImoocMallException(ImoocMallExceptionEnum.NAME_EXIST);
        }
//插入用户数据

        User newUser = new User();
        newUser.setUsername(username);
        newUser.setPassword(MD5Utils.getMD5(password));
//        newUser.setPassword(password);

        int count = userMapper.insertSelective(newUser);
        if (count == 0) {
throw new ImoocMallException(ImoocMallExceptionEnum.INSERT_FAILED);
        }
    }

@Override
    public User login(String userName, String password) throws NoSuchAlgorithmException, ImoocMallException {
        String passwordMd5 = MD5Utils.getMD5(password);
        User user = userMapper.selectLogin(userName, passwordMd5);
        if (user == null) {
throw new ImoocMallException(ImoocMallExceptionEnum.LOGIN_FAILED);
        }
return user;
    }

@Override
    public void updateInformation(User user) throws ImoocMallException {
int count = userMapper.updateByPrimaryKeySelective(user);
        if (count > 1) {
throw new ImoocMallException(ImoocMallExceptionEnum.UPDATE_FAILED);
        }
    }

@Override
    public Boolean checkAdminRole(User user){
return user.getRole().equals(2);
    }
}

package com.example.cloud.mall.exception;

//异常枚举
public enum ImoocMallExceptionEnum {
NEED_USER_NAME(10001,"用户名不能为空"),
    NEED_PASSWORD(10002,"密码不能为空"),
    PASSWORD_TOO_SHORT(10003,"密码不能小于8位"),
    NAME_EXIST(10004,"不允许重名"),
    INSERT_FAILED(10005,"插入失败"),
    LOGIN_FAILED(10006,"用户名或密码错误"),
    NEED_LOGIN(10007,"用户未登陆"),
    UPDATE_FAILED(10008,"更新失败"),
    NEED_ADMIN(10009,"无管理员权限"),
    NAME_NOT_NULL(10010,"参数不能为空"),
    CREATE_FAILED(10011,"新增失败"),
    REQUEST_PARAM_ERROR(10012,"参数错误"),
    DELETE_FAILED(10013,"删除失败"),
    MAKE_DIR_FAILED(10014,"文件夹创建失败"),
    UPLOAD_FAILED(10015,"图片上传失败"),
    NOT_SALE(10016,"商品状态不可售"),
    NOT_ENOUGH(10017,"商品库存不足"),
    CART_EMPTY(10018,"购物车已勾选的商品为空"),
    NO_ENUM(10019,"未找到对应的枚举类"),
    NO_ORDER(10020,"订单不存在"),
    NOT_YOUR_ORDER(10021,"订单不属于你"),
    WRONG_ORDER_STATUS(10021,"订单状态不符"),
    SYSTEM_ERROR(20000,"系统异常");

    Integer code;
    String msg;

    ImoocMallExceptionEnum(Integer code, String msg) {
this.code = code;
        this.msg = msg;
    }

public Integer getCode() {
return code;
    }

public void setCode(Integer code) {
this.code = code;
    }

public String getMsg() {
return msg;
    }

public void setMsg(String msg) {
this.msg = msg;
    }

@Override
    public String toString() {
return "ImoocMallExceptionEnum{" +
"code=" + code +
", msg='" + msg + '\'' +
'}';
    }
}

package com.example.cloud.mall.common;

import com.example.cloud.mall.exception.ImoocMallExceptionEnum;

//统一响应对象，根据文档设置响应对象的属性
public class ApiRestResponse<T> {
private Integer status;
    private String msg;
    private T data;

    private static final Integer OK_CODE = 10000;
    private static final String OK_MSG = "SUCCESS";

    public ApiRestResponse(Integer status, String msg, T data) {
this.status = status;
        this.msg = msg;
        this.data = data;
    }

public ApiRestResponse(Integer status, String msg) {
this.status = status;
        this.msg = msg;
    }

public ApiRestResponse() {
this(OK_CODE, OK_MSG);
    }

public static <T> ApiRestResponse<T> success() {
return new ApiRestResponse<>();
    }

public static <T> ApiRestResponse<T> success(T result){
        ApiRestResponse<T> apiRestResponse = new ApiRestResponse<>();
        apiRestResponse.setData(result);
        return apiRestResponse;
    }

public static <T> ApiRestResponse<T> error(Integer code, String msg) {
return new ApiRestResponse<>(code, msg);
    }

public static <T> ApiRestResponse<T> error(ImoocMallExceptionEnum ex) {
return new ApiRestResponse<>(ex.getCode(), ex.getMsg());
    }

public static Integer getOkCode() {
return OK_CODE;
    }

public static String getOkMsg() {
return OK_MSG;
    }

public Integer getStatus() {
return status;
    }

public void setStatus(Integer status) {
this.status = status;
    }

public String getMsg() {
return msg;
    }

public void setMsg(String msg) {
this.msg = msg;
    }

public T getData() {
return data;
    }

public void setData(T data) {
this.data = data;
    }
}

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