How to query department tree structure data recursively in Java

小编给大家分享一下Java中如何实现递归查询部门树形结构数据，希望大家阅读完这篇文章之后都有所收获，下面让我们一起去探讨吧!

说明：在开发中，我们经常使用树形结构来展示菜单选项，如图：

那么我们在后端怎么去实现这样的一个功能呢？

1、数据库表：department

2、编写sql映射语句

select * from department and UpDepartmentCode=#{updepartmentcode}

3、创建实体类

public class Department { private String departmentcode;//部门code private String departmentname;//部门名称 private String updepartmentcode="0";//上级部门 private String departmentdesc;//部门描述 private List childDept =new ArrayList();//部门信息树 public String getDepartmentcode() { return departmentcode; } public void setDepartmentcode(String departmentcode) { this.departmentcode = departmentcode == null ? null : departmentcode.trim(); } public String getDepartmentname() { return departmentname; } public void setDepartmentname(String departmentname) { this.departmentname = departmentname == null ? null : departmentname.trim(); } public String getUpdepartmentcode() { return updepartmentcode; } public void setUpdepartmentcode(String updepartmentcode) { this.updepartmentcode = updepartmentcode == null ? null : updepartmentcode.trim(); } public String getDepartmentdesc() { return departmentdesc; } public void setDepartmentdesc(String departmentdesc) { this.departmentdesc = departmentdesc == null ? null : departmentdesc.trim(); } public List getChildDept() { return childDept; } public void setChildDept(List childDept) { this.childDept = childDept; }}

4、定义mapper

@Mapperpublic interface DepartmentMapper { ListselectDepartmentTrees(Department department); }

5、定义service业务层实现

@Service@Transactionalpublic class DepartmentImpl implements IDepartmentService { @Resource DepartmentMapper departmentMapper; @Override public List selectDepartmentTrees(Department department) { return departmentMapper.selectDepartmentTrees(department); }}

6、控制层实现

@RestController@RequestMapping("department")public class DepartmentController { @Resource IDepartmentService departmentService; @Resource IStationService stationService; /** * 查询所华岗门 树形展示所华岗门 包含模糊查询 * * @return */ @RequestMapping("/treelist") public Object selectAll(Department department) { ModelMap map = new ModelMap(); try { List departmentDtos = getDepartmentList(department); map.put("msg", "查询部门成功"); map.put("data", departmentDtos); map.put("code", 0); } catch (Exception e) { e.printStackTrace(); map.put("msg", "查询部门失败"); map.put("code", 1); } return map; } /** * 递归查询部门 * @param department * @return */ private List getDepartmentList(Department department) { List departments =departmentService.selectDepartmentTrees(department); if (departments.size()>0){ Department department1=new Department(); for (int i = 0; i