如何用Java将MySQL企业、部门、职位数据转换为树形JSON结构？

[
  {
    "code": "c1",
    "name": "企业A",
    "departments": [
      {
        "code": "d1",
        "name": "财务部",
        "jobs": [
          {"code": "j1", "name": "财务主管"},
          {"code": "j2", "name": "会计"}
        ]
      },
      {
        "code": "d2",
        "name": "技术部",
        "jobs": [
          {"code": "j21", "name": "Java"},
          {"code": "j22", "name": "JS"}
        ]
      }
    ]
  },
  {
    "code": "c2",
    "name": "企业B",
    "departments": [
      {
        "code": "d20",
        "name": "销售部",
        "jobs": [{"code": "j20", "name": "销售员"}]
      }
    ]
  }
]

List<Company> data = new ArrayList<>();
Company curCompany;
Department curDepartment;
Map<String, Company> companyMap = new HashMap<>();
Map<String, Department> departmentMap = new HashMap<>();

for (Po po : records) { // records 为从数据库查询到的数据列表
    // 处理企业
    String companyKey = po.getCompanyCode();
    curCompany = companyMap.getOrDefault(companyKey, new Company());
    curCompany.setCode(po.getCompanyCode());
    curCompany.setName(po.getCompanyName());
    companyMap.put(companyKey, curCompany);
    if (!data.contains(curCompany)) { //避免重复添加企业
        data.add(curCompany);
    }

    // 处理部门
    String departmentKey = po.getCompanyCode() + po.getDeptCode();
    curDepartment = departmentMap.getOrDefault(departmentKey, new Department());
    curDepartment.setCode(po.getDeptCode());
    curDepartment.setName(po.getDeptName());
    departmentMap.put(departmentKey, curDepartment);
    curCompany.getDepartments().add(curDepartment);


    // 处理职位
    Job job = new Job();
    job.setCode(po.getJobCode()); //假设数据库字段名为JobCode
    job.setName(po.getJobName()); //假设数据库字段名为JobName
    curDepartment.getJobs().add(job);
}