update 修改用户信息，兼容教务端

mec-biz/src/main/java/com/ym/mec/biz/service/impl/StudentManageServiceImpl.java

@@ -566,9 +566,11 @@ public class StudentManageServiceImpl implements StudentManageService {
     public void updateUser(SysUser sysUser) {
         studentManageDao.updateUser(sysUser);
         Student student = studentDao.get(sysUser.getId());
-        student.setCurrentGradeNum(sysUser.getCurrentGradeNum());
-        student.setCurrentClass(sysUser.getCurrentClass());
-        studentDao.update(student);
+        if(student != null) {
+            student.setCurrentGradeNum(sysUser.getCurrentGradeNum());
+            student.setCurrentClass(sysUser.getCurrentClass());
+            studentDao.update(student);
+        }
 //        StudentRegistration studentRegistration = new StudentRegistration();
 //        studentRegistration.setUserId(sysUser.getId());
 //        studentRegistration.setCurrentClass(sysUser.getCurrentClass());