java递归查询省市区树形结构
具体代码实现如下:
@RequestMapping("getTree") public Map<String, Object> getTree(int id) { Map<String, Object> map = new HashMap<>(); try { ChinaCitys province = dao.findProvince(id); //查询出一个省 if (province != null) { List<ChinaCitys> citys = dao.findChildren(province.getId());//查询省下面的所有市 digui(citys); //调用递归算法查询市以下的区县 province.setChildren(citys); } map.put("data", province); } catch (Exception e) { e.printStackTrace(); } return map; } public void digui(List<ChinaCitys> citys) { List<ChinaCitys> retList = new ArrayList<>(); for (ChinaCitys c : citys) { retList = dao.findChildren(c.getId()); if (retList.size() > 0) { c.setChildren(retList); digui(retList); //循环调用自己 } } }
sql语句:
<select id="findProvince" parameterType="java.lang.Integer" resultMap="BaseResultMap"> select id,name from china_citys WHERE id = #{id} </select> <select id="findChildren" parameterType="java.lang.Integer" resultMap="BaseResultMap"> select id,name from china_citys WHERE upid = #{id} </select>