用戶登錄操作:
 
@Controller
public class LoginController {
 
    @Autowired
    private UserService userService;
    @Autowired
    private TeacherService teacherService;
    @Autowired
    private StudentService studentService;
 
    //跳轉登錄頁面
    @GetMapping("/login")
    public String login() {
        return "login";
    }
 
    //登錄操作
    @PostMapping("/login")
    @ResponseBody
    public Map<String, Object> login(String userName, String password, String captcha, String type, HttpSession session) {
        //判斷用戶名、密碼、用戶類型、驗證碼是否為空
        if (StringUtils.isEmpty(userName) || StringUtils.isEmpty(password) || StringUtils.isEmpty(captcha) || StringUtils.isEmpty(type)) {
            return MapControl.getInstance().error("用戶名或密碼不能為空").getMap();
        }
        //獲取系統生成的驗證碼
        String _captcha = (String) session.getAttribute("captcha");
        //先判斷驗證碼是否正確
        if (!(captcha.toLowerCase()).equals(_captcha.toLowerCase())) {
            //驗證碼錯誤
            return MapControl.getInstance().error("驗證碼錯誤").getMap();
        }
 
        //判斷用戶類型
        if ("1".equals(type)) { //管理員驗證登錄
            User user = userService.login(userName, MD5Utils.getMD5(password)); //對密碼進行加密處理，因為數據庫中存儲的是加密后的密碼
            if (user != null) {
                session.setAttribute("user", user);
                session.setAttribute("type", 1);
                return MapControl.getInstance().success().add("data", user).getMap();
            } else {
                return MapControl.getInstance().error("用戶名或密碼錯誤").getMap();
            }
        }
        if ("2".equals(type)) { //老師驗證登錄
            Teacher teacher = teacherService.login(userName, MD5Utils.getMD5(password));
            if (teacher != null) {
                session.setAttribute("user", teacher);
                session.setAttribute("type", "2");
                return MapControl.getInstance().success().add("data", teacher).getMap();
            } else {
                return MapControl.getInstance().error("用戶名或密碼錯誤").getMap();
            }
        }
        if ("3".equals(type)) { //學生驗證登錄
            Student student = studentService.login(userName, MD5Utils.getMD5(password));
            if (student != null) {
                session.setAttribute("user", student);
                session.setAttribute("type", "3");
                return MapControl.getInstance().success().add("data", student).getMap();
            } else {
                return MapControl.getInstance().error("用戶名或密碼錯誤").getMap();
            }
        }
        return MapControl.getInstance().getMap();
    }
 
}

用戶登出操作:
 
@Controller
public class LogoutController {
 
    //退出操作
    @RequestMapping("/logout")
    public String logout(HttpSession session) {
        //讓session失效
        session.invalidate();
        //重定向到登錄頁
        return "redirect:login";
    }
 
}