递归查询部门以及部门下的成员列表

1、表结构

2、代码

 @GetMapping(value = "/getAllDepartment")
    public String getAllDepartment() {
        List<Department> departments = departmentDao.selectByParentId(0);
        List<DepartmentResp> list = new ArrayList<>();
        if (departments.size() > 0) {
            departments.stream().forEach(department -> {
                DepartmentResp departmentResp = new DepartmentResp();
                departmentResp.setId(department.getId());
                departmentResp.setParentId(department.getParentId());
                departmentResp.setName(department.getName());
                List<DepartmentResp> children = getChildren(department.getId());
                departmentResp.setFlag(children.size()>0);
                departmentResp.setChildrenList(children);
                //查询当前人
                List<User> users = userDao.selectByDepartmentId(department.getId());
                departmentResp.setUserList(users);
                list.add(departmentResp);
            });
        }
        String s = JSONObject.toJSONString(list);
        return s;
    }
 
    public List<DepartmentResp> getChildren(Integer parentId) {
        List<DepartmentResp> list = new ArrayList<>();
        List<Department> departments = departmentDao.selectByParentId(parentId);
        departments.stream().forEach(department -> {
            DepartmentResp departmentResp = new DepartmentResp();
            departmentResp.setId(department.getId());
            departmentResp.setParentId(department.getParentId());
            departmentResp.setName(department.getName());
            List<DepartmentResp> children = getChildren(department.getId());
            departmentResp.setFlag(children.size()>0);
            departmentResp.setChildrenList(children);
            //查询当前人
            List<User> users = userDao.selectByDepartmentId(department.getId());
            departmentResp.setUserList(users);
            list.add(departmentResp);
        });
        return list;
    }

3、原理介绍

1.先根据根部门0查询根部门下的部门列表。
2.然后遍历部门列表。
3.然后每个部门下都查询子部门以及当前部门下的人员（调用getChildren（）方法）。
4.查询子方法是又将id作为父id，再次调用子方法本身（调用getChildren（）方法），如此反复即可实现。