style: formatting

src/main/java/nju/seec/helper/controller/UserController.java

@@ -10,7 +10,6 @@ import nju.seec.helper.service.UserService;
 import nju.seec.helper.util.Consts;
 import nju.seec.helper.util.enums.UserType;
 import nju.seec.helper.vo.UserVO;
-import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
 import javax.servlet.http.HttpSession;

src/main/java/nju/seec/helper/service/CourseService.java

@@ -8,8 +8,6 @@ import nju.seec.helper.vo.CourseVO;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 
-import java.util.List;
-
 /**
  * @author cst
  */

src/main/java/nju/seec/helper/service/SlideService.java

@@ -8,8 +8,6 @@ import nju.seec.helper.vo.SlideVO;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 
-import java.util.List;
-
 /**
  * @author cst
  */