mybatis - 为什么Java后端用Boolean属性筛选不出对象,但改成String类型就可以了?

 public JSONArray getTreeNodes(String departmentSn) {
        Department department = new Department();
        JSONArray jsonArray = new JSONArray();
        if (!departmentSn.equals("-1")) {
            department.setParentDepartmentSn(departmentSn);
        } else {
//这里将department的一个布尔属性设置为true
         department.setHasActivated(true);
        }
//在这里进行筛选
        List<Department> departments = departmentMapper.select(department);
        System.out.print(departments);
        for (Department DEP : departments) {
            Department d = new Department();
            Department sonDepartment = departmentMapper.selectByPrimaryKey(DEP.getDepartmentSn());
            JSONObject jsonObject = new JSONObject();
            jsonObject.put("label", sonDepartment.getDepartmentName());
            jsonObject.put("data", sonDepartment.getDepartmentSn());
            d.setParentDepartmentSn(DEP.getDepartmentSn());
            if (departmentMapper.selectCount(department) == 0) {
                jsonObject.put("leaf", true);
            } else {
                jsonObject.put("leaf", false);
            }
            jsonArray.add(jsonObject);
        }
        return jsonArray;
    }
}

在上面的代码中,当我传入一个不为-1的departmentSn进来时,它并没有进入else分支,然而经过下面的筛选后结果集为空,如下图

此处size为0.
而当我将实体类中的boolean属性改为string属性后(如图)

修改前

修改后

筛选结果就正常了.

此处size为8.
这是为什么呢?
另外,我还尝试了手动将boolean属性赋为false,结果同样为空.如下图.