我在 Spring 处理一些dao文件，我的beanpropertyrowmapper有一些问题。它正确Map了几个属性，但对于一个属性，它返回null。为什么会这样？下面是我的读条目dao方法：

@Override
public Optional<Activity> read(Long id) {
    try {
        return Optional.ofNullable(jdbcTemplate.queryForObject("SELECT * FROM activities WHERE id=?", new BeanPropertyRowMapper<>(Activity.class), id));
    } catch (EmptyResultDataAccessException e) {
        return Optional.empty();
    }
}

这是我的模型：

public class Activity implements Entity<Long> {
private Long id;
private Long groupId;
private Long classRoomId;
private Long lessonNumber;
private Long courseId;

public Activity() {
}

public Activity(Long id, Long groupId, Long classRoomId, Long lessonNumber, Long courseId) {
    this.id = id;
    this.groupId = groupId;
    this.classRoomId = classRoomId;
    this.lessonNumber = lessonNumber;
    this.courseId = courseId;
}

public Activity(Long groupId, Long classRoomId, Long lessonNumber, Long courseId) {
    this.groupId = groupId;
    this.classRoomId = classRoomId;
    this.lessonNumber = lessonNumber;
    this.courseId = courseId;
}

public Long getGroupId() {
    return groupId;
}

public void setGroupId(Long groupId) {
    this.groupId = groupId;
}

public Long getClassRoomId() {
    return classRoomId;
}

public void setClassRoomId(Long classRoomId) {
    this.classRoomId = classRoomId;
}

public Long getLessonNumber() {
    return lessonNumber;
}

public void setLessonNumber(Long lessonNumber) {
    this.lessonNumber = lessonNumber;
}

public Long getCourseId() {
    return courseId;
}

public void setCourseId(Long courseId) {
    this.courseId = courseId;
}

@Override
public Long getId() {
    return id;
}

@Override
public void setId(Long id) {
    this.id = id;
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Activity activity = (Activity) o;

    if (groupId != null ? !groupId.equals(activity.groupId) : activity.groupId != null) return false;
    if (classRoomId != null ? !classRoomId.equals(activity.classRoomId) : activity.classRoomId != null)
        return false;
    if (lessonNumber != null ? !lessonNumber.equals(activity.lessonNumber) : activity.lessonNumber != null)
        return false;
    return courseId != null ? courseId.equals(activity.courseId) : activity.courseId == null;
}

@Override
public int hashCode() {
    int result = groupId != null ? groupId.hashCode() : 0;
    result = 31 * result + (classRoomId != null ? classRoomId.hashCode() : 0);
    result = 31 * result + (lessonNumber != null ? lessonNumber.hashCode() : 0);
    result = 31 * result + (courseId != null ? courseId.hashCode() : 0);
    return result;
}

@Override
public String toString() {
    return String.format("id is %s, groupId is %s, classRoomId is %s, lessonNumber is %s, courseId is %s",
            this.id, this.groupId, this.classRoomId, this.lessonNumber, this.courseId);
}
}

下面是我的junit测试方法：

@Test
void read() throws Exception {
    Activity expected = new Activity(100L, 100L,1L,100L);
    Long id = activityDao.save(expected).getId();
    if(activityDao.read(id).isPresent()){
        Activity actual = activityDao.read(id).get();
        assertEquals(expected, actual);
    }else {
        fail("Not found");
    }
}

下面是我的junit测试方法返回的结果：
org.opentest4j.assertionfailederror:预期：id为null，groupid为100，教室id为100，lessonnumber为1，courseid为100实际：id为1，groupid为100，教室id为null，lessonnumber为1，courseid为100
编辑：这是我的数据库表：在这里输入图像描述
编辑：稍微更改了dao方法，以便属性和表列匹配：

@Override
public Optional<Activity> read(Long id) {
    try {
        return Optional.ofNullable(jdbcTemplate.queryForObject("SELECT a.id as id,  a.group_id as groupId, a.classroom_id as classRoomId, a.lessonnumber as lessonNumber," +
                " a.course_id as courseId FROM activities a WHERE id=?", new BeanPropertyRowMapper<>(Activity.class), id));
    } catch (EmptyResultDataAccessException e) {
        return Optional.empty();
    }
}

然而，这是行不通的。