list集合多线程分批导入Mysql

public int addFreshStudentsNew(List<FreshStudentAndStudentModel> list, String schoolNo) {
    if (list == null || list.isEmpty()) {
        return 0;
    }
    List<StudentEntity> studentEntityList = new LinkedList<>();
    List<EnrollStudentEntity> enrollStudentEntityList = new LinkedList<>();
    List<AllusersEntity> allusersEntityList = new LinkedList<>();

    list.forEach(freshStudentAndStudentModel -> {
        EnrollStudentEntity enrollStudentEntity = new EnrollStudentEntity();
        StudentEntity studentEntity = new StudentEntity();
        BeanUtils.copyProperties(freshStudentAndStudentModel, studentEntity);
        BeanUtils.copyProperties(freshStudentAndStudentModel, enrollStudentEntity);
        String operator = TenancyContext.UserID.get();
        String studentId = BaseUuidUtils.base58Uuid();
        enrollStudentEntity.setId(BaseUuidUtils.base58Uuid());
        enrollStudentEntity.setStudentId(studentId);
        enrollStudentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        enrollStudentEntity.setOperator(operator);
        studentEntity.setId(studentId);
        studentEntity.setIdentityCardId(freshStudentAndStudentModel.getIdCard());
        studentEntity.setOperator(operator);
        studentEntityList.add(studentEntity);
        enrollStudentEntityList.add(enrollStudentEntity);
    
        AllusersEntity allusersEntity = new AllusersEntity();
        allusersEntity.setId(enrollStudentEntity.getId());
        allusersEntity.setUserCode(enrollStudentEntity.getNemtCode());
        allusersEntity.setUserName(enrollStudentEntity.getName());
        allusersEntity.setSchoolNo(schoolNo);
        allusersEntity.setTelNum(enrollStudentEntity.getTelNum());
        allusersEntity.setPassword(enrollStudentEntity.getNemtCode());  //密码设置为考生号
        allusersEntityList.add(allusersEntity);
    });


    int nThreads = 50;
    
    int size = enrollStudentEntityList.size();
    ExecutorService executorService = Executors.newFixedThreadPool(nThreads);
    List<Future<Integer>> futures = new ArrayList<Future<Integer>>(nThreads);
    
    for (int i = 0; i < nThreads; i++) {
        final List<EnrollStudentEntity> EnrollStudentEntityImputList = enrollStudentEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));
        final List<StudentEntity> studentEntityImportList = studentEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));
        final List<AllusersEntity> allusersEntityImportList = allusersEntityList.subList(size / nThreads * i, size / nThreads * (i + 1));
    
       Callable<Integer> task1 = () -> {
      studentSave.saveStudent(EnrollStudentEntityImputList,studentEntityImportList,allusersEntityImportList);
           return 1;
        };
      futures.add(executorService.submit(task1));
    }
    executorService.shutdown();
    if (!futures.isEmpty() && futures != null) {
        return 10;
    }
    return -10;
}