小张推荐:瑞吉外卖Day01，瑞吉外卖Day03

1.登陆功能

1.1结果封装类

• 导入返回结果类R此类是一个通用结果类。
• 服务端响应的所有结果最终都会包装成此种类型返回给前端页面

注意属性名，莫要写错，不然与前端很难对接！！！！ 

/**
 * 通用返回结果
 * @param <T>
 */
@Data
public class R<T> {
    private Integer code;//编码：1：成功，0：失败
    private String msg;//错误信息
    private T data;//数据
    private Map map=new HashMap();//动态数据


    /**
     * 响应成功
     * @param object
     * @param <T>
     * @return
     */
    public static <T>R<T> success(T object){
        R<T> r=new R<>();
        r.data=object;
        r.code=1;
        return r;
    }

    /**
     * 响应错误
     * @param mgs
     * @param <T>
     * @return
     */
    public static <T>R<T> error(String mgs){
        R<T> r=new R<>();
        r.mgs=mgs;
        r.code=0;
        return r;
    }

    public R<T> add(String key,Object value){
        this.map.put(key,value);
        return this;
    }
}

 1.2实体类

/**
 * 员工实体类
 */
@Data
@TableName("employee")
@NoArgsConstructor
@AllArgsConstructor
public class Employee {

    private Long id;
    private String username;
    private String name;
    private String password;
    private String phone;
    private String sex;
    private String idNumber;
    private Integer status;
    private LocalDateTime createTime;
    private LocalDateTime updateTime;
    private Long createUser;
    private Long updateUser;
}

1.3mapper层

@Repository
@Mapper
public interface EmployeeMapper extends BaseMapper<Employee> {

}

1.4Service层

public interface EmployeeService extends IService<Employee> {

}

@Service
public class EmployeeServiceImpl extends ServiceImpl<EmployeeMapper, Employee> implements EmployeeService {

}

1.5Controller层

    @Autowired
    private EmployeeService employeeService;


    /**
     * 登录
     */
    @PostMapping("/login")
    public R<Employee> login(@RequestBody Employee employee, HttpServletRequest request) {
        //md5加密
        String password = employee.getPassword();
        password = DigestUtils.md5DigestAsHex(password.getBytes());

        //查数据库
        LambdaQueryWrapper<Employee> queryWrapper = new LambdaQueryWrapper();
        queryWrapper.eq(Employee::getUsername, employee.getUsername());
        Employee emp = employeeService.getOne(queryWrapper);

        //判断是否有用户
        if (emp == null) {
            return R.error("用户不存在~");
        }
        //判断密码
        if (!emp.getPassword().equals(password)) {
            return R.error("密码错误,请重新输入~");
        }
        //判断状态
        if (emp.getStatus() == 0) {
            return R.error("该账号已禁用！！！");
        }
        //登陆成功，将员工id存入Session并返回登陆成功
        request.setAttribute("employee", emp.getId());
        return R.success(emp);
    }

2.退出功能

2.1Controller层

  /**
     * 退出
     */

    @PostMapping("/logout")
    public R<String> logout(HttpServletRequest request) {
        //清除session中保存的当前登陆者的id
        request.getSession().removeAttribute("employee");
        return R.success("退出成功");
    }

2.2添加登录拦截

• 存在一个问题：用户如果不登录，直接访问系统首页面，照样可以正常访问。
• 解决:使用过滤器或者拦截器,在过滤器或者拦截器中判断用户是否已经完成登录,如果没有登录则跳转到登录页面。

• 记得主程序类上添加@ServletComponentScan 

@Slf4j
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    //路径匹配器
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1.获取本次请求的uri
        String requestURI = request.getRequestURI();
        log.info("拦截到请求：{}",requestURI);

        //2.定义放行的请求路径
        String[] urls = new String[]{"/employee/login", "/employee/logout", "/backend/**", "/front/**"};

        //3.判断本次请求是否需要处理
        boolean check = check(urls,requestURI);


        //4.如果不需要处理，直接放行
        if (check) {//true，不需要处理
            log.info("本次请求不需要处理{}",requestURI);
            //放行
            filterChain.doFilter(request, response);
            return;
        }

        //5.判断当前登陆状态，如果已经登录，则直接放行
        Object employee = request.getSession().getAttribute("employee");
       log.info("用户:"+employee);
        if (request.getSession().getAttribute("employee") != null) {
            log.info("后台用户已登录，用户id:{}",request.getSession().getAttribute("employee"));
            filterChain.doFilter(request, response);
            return;
        }

        log.info("用户未登录");
        //6.如果未登录，返回未登录结果，通过输出流向客户端响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }

    /**
     * 路径匹配，是否需要放行
     *
     * @param requestURI
     * @param urls
     * @return
     */
    public boolean check(String[] urls,String requestURI) {
        //循环放行的路径的数组
        for (String url : urls) {
            //当前路径是否与放行路径匹配
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                //不需要处理
                return true;
            }
        }
        //需要处理
        return false;
    }
}

3.新增员工

3.1controller层

 /**
     *新增员工
     */
    @PostMapping
    public R<String> save(@RequestBody Employee employee,HttpServletRequest request){
        log.info("新增员工,员工信息:{}",employee.toString());
        //设置初始密码123456，但需要MD5加密
        employee.setPassword(DigestUtils.md5DigestAsHex("123456".getBytes()));
        employee.setCreateTime(LocalDateTime.now());
        employee.setUpdateTime(LocalDateTime.now());

        //获取当前登录用户的id
        Long id = (Long) request.getSession().getAttribute("employee");
        employee.setCreateUser(id);
        employee.setUpdateUser(id);
        employeeService.save(employee);
        return R.success("新增员工成功");
    }

3.2美中不足 

• 因为数据库中的username字段设置了唯一标识，当添加相同账号时，会抛出异常：java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '666888' for key 'employee.idx_username'

3.3完美解决 

• 1.添加try-cratch捕获，这种方法会导致后面要写大量try-catch
• 2.添加全局异常处理器（推荐）

@ControllerAdvice(annotations = {RestController.class, Controller.class})
@ResponseBody
@Slf4j
public class GlobalExceptionHandler {

    /**
     * 异常处理方法
     * @return
     */
    @ExceptionHandler(SQLIntegrityConstraintViolationException.class)
    public R<String> exceptionHandler(SQLIntegrityConstraintViolationException exception){
        log.error(exception.getMessage());

        if (exception.getMessage().contains("Duplicate entry")){
            String[] arr = exception.getMessage().split(" ");
            String msg=arr[2]+"已存在";
            return R.error(msg);
        }
        return R.error("未知错误");
    }
}

 3.5@ControllerAdvice作用

• 1·结合方法型注解@ExceptionHandler,用于捕获Controller中抛出的指定类型的异常,从而达到不同类型的异常区别处理的目的。
• 2·结合方法型注解@InitBinder,用于request中自定义参数解析方式进行注册,从而达到自定义指定格式参数的目的
• 3.结合方法型注解@ModelAttribute,表示其注解的方法将会在目标Controller方法执行之前执行。

4.员工信息分页查询

4.1添加分页插件

@Configuration
public class MybatisPlusConfig {
    
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor mybatisPlusInterceptor=new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return mybatisPlusInterceptor;
    }
}

4.2分页查询

   @GetMapping("/page")
    public R<Page> page(int page, int pageSize, String name) {
        log.info("page:{},pageSize:{},name:{}",page,pageSize,name);
        //构造分页构造器
        Page pageInfo=new Page(page,pageSize);
        //构造条件构造器
        LambdaQueryWrapper<Employee> queryWrapper=new LambdaQueryWrapper<>();
        //过滤条件
        queryWrapper.like(StringUtils.isNotEmpty(name),Employee::getName,name);
        //排序条件
        queryWrapper.orderByDesc(Employee::getUpdateTime);
        //分页查询
        employeeService.page(pageInfo,queryWrapper);
        return R.success(pageInfo);
    }