Java 递归查询部门树形结构数据的实践
作者：哥的冷酷，你模仿不来
本文主要介绍了Java 递归查询部门树形结构数据的实践，文中通过示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
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 id="selectDepartmentTrees" resultType="com.welb.entity.Department">
select * from department
<where>
<if test="updepartmentcode!=null">
and UpDepartmentCode=#{updepartmentcode}
</if>
</where>
</select>
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<Department> 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<Department> getChildDept() {
return childDept;
}
public void setChildDept(List<Department> childDept) {
this.childDept = childDept;
}
}
4、定义mapper
@Mapper
public interface DepartmentMapper {
List<Department>selectDepartmentTrees(Department department);
}
5、定义service业务层实现
@Service
@Transactional
public class DepartmentImpl implements IDepartmentService {
@Resource
DepartmentMapper departmentMapper;
@Override
public List<Department> 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<Department> 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<Department> getDepartmentList(Department department) {
List<Department> departments =departmentService.selectDepartmentTrees(department);
if (departments.size()>0){
Department department1=new Department();
for (int i = 0; i <departments.size() ; i++) {
department1.setUpdepartmentcode(departments.get(i).getDepartmentcode());
List<Department>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
到这里，递归查询部门树形结构数据就完成了
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