=============
后端_用户登录
=============

用户登录：

- 验证账号密码
- 为用户生成令牌
- 将令牌和用户的信息保存在Redis中
- 将令牌返回前端

1 添加依赖

/ysdblog-api/pom.xml：

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
</dependency>

2 配置Redis

/ysdblog-api/src/main/resources/application.properties：

...
# Redis
spring.redis.host=localhost
spring.redis.port=6379
...

3 错误码枚举

/ysdblog-api/src/main/java/com/weihome/ysdblog/vo/ErrorCode.java：

public enum  ErrorCode {
    PARAM_ERROR(10001, "参数有误"),
    ACCOUNT_PWD_NOT_EXIST(10002, "用户名或密码不存在"),
    TOKEN_ERROR(10003, "令牌有误"),
    ACCOUNT_EXIST(10004, "账号已存在"),
    UPLOAD_ERROR(20001, "上传失败"),
    NO_PERMISSION(70001, "无访问权限"),
    SESSION_TIME_OUT(90001, "会话超时"),
    NO_LOGIN(90002, "未登录"),;

    private Integer code;
    private String msg;

    ErrorCode(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;
    }
}

4 视图对象

4.1 登录参数视图对象

/ysdblog-api/src/main/java/com/weihome/ysdblog/vo/params/LoginParam.java：

@Data
public class LoginParam {
    private String account;
    private String password;
}

5 用户服务

5.1 用户服务接口

/ysdblog-api/src/main/java/com/weihome/ysdblog/service/UserService.java：

public interface UserService {
    ...
    /**
     * 根据账号密码查询用户
     */
    public User findUser(String account, String password);
    ...
}

5.2 用户服务实现

/ysdblog-api/src/main/java/com/weihome/ysdblog/service/impl/UserServiceImpl.java：

...
public class UserServiceImpl implements UserService {
    ...
    @Override
    public User findUser(String account, String password) {
        LambdaQueryWrapper<User> queryWrapper =
            new LambdaQueryWrapper<>();
        queryWrapper.eq(User::getAccount, account);
        queryWrapper.eq(User::getPassword, password);
        queryWrapper.select(User::getId, User::getAccount,
            User::getAvatar, User::getNickname);
        queryWrapper.last("limit 1");
        return userMapper.selectOne(queryWrapper);
    }
    ...
}

6 登录服务

6.1 登录服务接口

/ysdblog-api/src/main/java/com/weihome/ysdblog/service/LoginService.java：

public interface LoginService {
    /**
     * 用户登录
     */
    public Result login(LoginParam loginParam);
}

6.2 登录服务实现

/ysdblog-api/src/main/java/com/weihome/ysdblog/service/impl/LoginServiceImpl.java：

@Service
public class LoginServiceImpl implements LoginService {
    @Autowired
    private UserService userService;

    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    @Override
    public Result login(LoginParam loginParam) {
        String account = loginParam.getAccount();
        String password = loginParam.getPassword();

        // 检查账号密码是否合法
        if (StringUtils.isBlank(account) ||
            StringUtils.isBlank(password))
            return Result.fail(
                ErrorCode.PARAM_ERROR.getCode(),
                ErrorCode.PARAM_ERROR.getMsg());

        // 检查账号密码是否存在
        User user = userService.findUser(account,
            DigestUtils.md5Hex(password + salt));
        if (user == null)
            return Result.fail(
                ErrorCode.ACCOUNT_PWD_NOT_EXIST.getCode(),
                ErrorCode.ACCOUNT_PWD_NOT_EXIST.getMsg());

        // 为该用户生成令牌
        String token = JWTUtils.createToken(user.getId());

        // 将令牌和用户的对应关系保存到Redis中并将过期时间设置为1天
        redisTemplate.opsForValue().set("TOKEN_" + token,
            JSON.toJSONString(user), 1, TimeUnit.DAYS);

        // 返回令牌给前端
        return Result.success(token);
    }

    public static void main(String[] args) {
        System.out.println(
            DigestUtils.md5Hex("123456" + salt));
    }
}

7 登录控制器

/ysdblog-api/src/main/java/com/weihome/ysdblog/controller/LoginController.java：

@RestController
@RequestMapping("login")
public class LoginController {
    @Autowired
    private LoginService loginService;
    /**
     * 用户登录
     */
    @PostMapping
    public Result login(@RequestBody LoginParam loginParam) {
        return loginService.login(loginParam);
    }
}

8 运行测试

Postman
    POST
        localhost:8888/login
    Body
{
    "account": "user_a",
    "password": "123456"
}
----------------------------
{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": "eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2NDk1NzgzNjUsInVzZXJJZCI6MSwiaWF0IjoxNjQ4Njg5MzMyfQ.GSsoLNluJwDseqaglBBvKmMZdtdBapInPdnTHs3oXv8"
}

检查Redis库，新增如下键值对：

键：TOKEN_eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2NDk1NzgzNjUsInVzZXJJZCI6MSwiaWF0IjoxNjQ4Njg5MzMyfQ.GSsoLNluJwDseqaglBBvKmMZdtdBapInPdnTHs3oXv8
值：{"account":"user_a","avatar":"user_a.png","id":1,"nickname":"nickname_a"}