Java|Java 递归查询部门树形结构数据的实践 Java递归查询部门树形结构数据

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：

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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

【Java|Java 递归查询部门树形结构数据的实践】
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2、编写sql映射语句

select * from departmentand UpDepartmentCode=#{updepartmentcode}

3、创建实体类

public class Department {private String departmentcode; //部门codeprivate 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 {@ResourceDepartmentMapper departmentMapper; @Overridepublic List selectDepartmentTrees(Department department) {return departmentMapper.selectDepartmentTrees(department); }}

6、控制层实现

@RestController@RequestMapping("department")public class DepartmentController {@ResourceIDepartmentService departmentService; @ResourceIStationService stationService; /*** 查询所有部门树形展示所有部门包含模糊查詢** @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 dtos=getDepartmentList(department1); departments.get(i).setChildDept(dtos); }}return departments; }}

7、进行测试，这里我用postmain工具测试，结果如下图