登录功能开发, 主要是要校验登录账号及密码的准确性, 注意密码使用 base64 加密.
另外一个最重要的是要记住当前用户的id以记住登录状态, 并使用拦截器, 对于部分请求, 需要先校验登录状态, 若校验成功才放行.

1. 创建实体类

登录业务逻辑涉及到的是员工的登录与管理, 创建 Employee 实体类, 它包装 MySQL 查询返回的数据:

package com.rain.reggie.entity;import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import lombok.Data;
import java.io.Serializable;
import java.time.LocalDateTime;/*** 员工实体*/
@Data
public class Employee implements Serializable {private static final long serialVersionUID = 1L;private Long id;private String username;private String name;private String password;private String phone;private String sex;private String idNumber;//身份证号码private Integer status;private LocalDateTime createTime;private LocalDateTime updateTime;@TableField(fill = FieldFill.INSERT)private Long createUser;@TableField(fill = FieldFill.INSERT_UPDATE)private Long updateUser;
}

2. 创建三层调用结构

mapper

创建 mapper 层, 它负责实际的数据库操作, 同时借助于 mybatisplus, 它的编写十分简洁:

package com.rain.reggie.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.rain.reggie.entity.Employee;
import org.apache.ibatis.annotations.Mapper;@Mapper
public interface EmployeeMapper extends BaseMapper<Employee>{
}

接口先被声明为 Mapper 接口, 接着它继承了 mybatisplus 中的 BaseMapper, 同时指明泛型类型为 Employee.

service

创建 service 层, 该层负责接受 controller 的业务需求, 调用 Mapper 层完成业务逻辑开发.
对于 service 层, 需要设计接口和实现类:

package com.rain.reggie.service;import com.baomidou.mybatisplus.extension.service.IService;
import com.rain.reggie.entity.Employee;public interface EmployeeService extends IService<Employee> {
}

package com.rain.reggie.service.impl;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.rain.reggie.entity.Employee;
import com.rain.reggie.mapper.EmployeeMapper;
import com.rain.reggie.service.EmployeeService;
import org.springframework.stereotype.Service;@Service
public class EmployeeServiceImpl extends ServiceImpl<EmployeeMapper,Employee> implements EmployeeService{
}

注意实现类先继承了 ServiceImpl, 指明泛型类型, 接着实现了 EmployeeService 接口.

controller

来到顶层的设计 controller 层, 该层负责接受前端发送的请求, 解析请求参数, 调用 service 层获得结果, 将结果封装后返回前端.

注意请求路径、请求方式、响应结果的形式、请求需要完成的功能等等在 API 文档中有明确规定.
这里需要创建一个通用的数据返回实体类, 包括数据内容/消息/响应码. 另外还包含一个临时字典.

public class R<T>{private String msg;private Integer code;private T data;private Map map = new HashMap(); //动态数据public static <T> R<T> success(T object) {R<T> r = new R<T>();r.data = object;r.code = 1;return r;}public static <T> R<T> error(String msg) {R r = new R();r.msg = msg;r.code = 0;return r;}public R<T> add(String key, Object value) {this.map.put(key, value);return this;}
}

3. 登录逻辑实现

员工登录

1. 获取密码并进行md5加密
2. 查询数据库校验是否存在该用户(用户名)
3. 不存在则直接返回失败信息
4. 否则继续校验密码
5. 不匹配则直接返回失败信息
6. 否则继续校验用户状态
7. 若为禁用状态则返回失败信息
8. 否则登陆成功, 返回成功信息, 同时向请求中写入登录信息, 也即员工ID.

注意 mybatisplus 的使用方法:

package com.rain.reggie.controller;@Slf4j
@RestController
@RequestMapping("/employee")
public class EmployeeController {@Autowiredprivate EmployeeService employeeService;// http://localhost:8080/backend/page/login/login.html@PostMapping("/login")public R<Employee> login(HttpServletRequest request, @RequestBody Employee employee){LambdaQueryWrapper<Employee> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(Employee::getUsername, employee.getUsername());Employee query = employeeService.getOne(queryWrapper);String pwd = employee.getPassword();pwd = DigestUtils.md5DigestAsHex(pwd.getBytes())if (query == null)return R.error("用户不存在");if (!query.getPassword().equals(pwd))return R.error("密码错误");if (query.getStatus() == 0)return R.error("账户已停用");request.getSession().setAttribute("employee", result.getId());return R.success(query);}// 登出@PostMapping("/logout")public R<String> logout(HttpServletRequest request){//清理Session中保存的当前登录员工的idrequest.getSession().removeAttribute("employee");return R.success("退出成功");}
}

4. 过滤器/拦截器

为了实现未登录则无法访问后台资源的效果, 需要编写过滤器或者拦截器, 这里采用过滤器.
实现的关键点在于 @WebFilter 注解和重写 doFilter() 方法
先获取到请求路径, 检查路径是否需要拦截, 不需要拦截的例如登入登出请求以及静态资源访问请求等.
对于需要拦截的, 检查会话中是否存储 “employee” 键值对, 若检查到该键值对, 表示已登录
直接放行, 否则向响应中写入错误状态字符串.

package com.rain.reggie.filter;@Slf4j
@WebFilter(filterName = "loginFilter", urlPatterns = "/*")
public class LoginFilter implements Filter {@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest) servletRequest;HttpServletResponse response = (HttpServletResponse) servletResponse;String uri = request.getRequestURI();log.info("拦截到请求{}", uri);if (ok(uri)){log.info("本次请求{}不需要处理", uri);filterChain.doFilter(request, response);return;}if (null != request.getSession().getAttribute("employee")){log.info("已登录");filterChain.doFilter(request, response);return;}log.info("未登录");response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));}private static boolean ok(String uri){AntPathMatcher matcher = new AntPathMatcher();String[] ok_list = {"/employee/login","/employee/logout","/backend/**","/front/**"};for (String u: ok_list){if (matcher.match(u, uri))return true;}return false;}
}

注意为了使过滤器生效, 需要添加 Servlet 包扫描注解.

package com.rain.reggie;@SpringBootApplication
@ServletComponentScan
public class Reggie001Application {public static void main(String[] args) {SpringApplication.run(Reggie001Application.class, args);}}