java递归算法实现拼装树形JSON数据
有时候页面需要使用jQuery easy ui中的combotree，需要给combotree提供一个JSON数据，使用如下方法（递归）实现(下面是dao层的实现层)：
/** * 根据表名和父id拼装树形JSON数据 * @param tableName * @param parentId * @return * @throws Exception */ @Override public String createTreeJsonBytableNameAndParentId(String tableName,String parentId) throws Exception { Map<String, Object> map = new HashMap<String, Object>(); List<Map<String, Object>> list = new ArrayList<Map<String,Object>>(); String sql = " select * from " + tableName + " where 1 = 1 "; if (StringUtils.isNotEmpty(parentId)) { sql = sql + " and parent_id = '" + parentId + "'"; }else { sql = sql + " and parent_id is null"; } Session session = getSession(); Query query = session.createSQLQuery(sql); //存储过程键值对应 query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP); List<Map<String,String>> lists = query.list(); for (Map<String,String> msp : lists) { map = new HashMap<String, Object>(); List<Map<String, Object>> list_children = new ArrayList<Map<String,Object>>(); String id = msp.get("id"); map.put("id",msp.get("code")); map.put("text",msp.get("name")); list_children = createTreeChildJson(tableName,id); if (list_children.size()>0) { map.put("state","closed"); map.put("children", list_children); } list.add(map); } JSONArray arry = JSONArray.fromObject(list); return arry.toString(); } /** * 根据表名和父id拼装树形LIST数据递归 * @param tableName * @param parentId * @return * @throws Exception */ private List<Map<String, Object>> createTreeChildJson(String tableName,String parentId) throws Exception { Map<String, Object> map = new HashMap<String, Object>(); List<Map<String, Object>> list = new ArrayList<Map<String,Object>>(); String sql = " select * from " + tableName + " where 1 = 1 "; if (StringUtils.isNotEmpty(parentId)) { sql = sql + " and parent_id = '" + parentId + "'"; }else { sql = sql + " and parent_id is null"; } Session session = getSession(); Query query = session.createSQLQuery(sql); //存储过程键值对应 query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP); List<Map<String,String>> lists = query.list(); for (Map<String,String> msp : lists) { map = new HashMap<String, Object>(); List<Map<String, Object>> list_children = new ArrayList<Map<String,Object>>(); String id = msp.get("id"); map.put("id",msp.get("code")); map.put("text",msp.get("name")); list_children = createTreeChildJson(tableName,id); if (list_children.size()>0) { map.put("state","closed"); map.put("children", list_children); } list.add(map); } return list; }
拼装好的数据如下：
[ { "id": "09DE010000", "text": "漳卫新河", "state": "closed", "children": [ { "id": "09DE010100", "text": "四女寺减河" }, { "id": "09DE010200", "text": "岔河" }, { "id": "09DE010300", "text": "六五河" } ] }, { "id": "09DE020000", "text": "马颊河", "state": "closed", "children": [ { "id": "09DE020100", "text": "笃马河", "state": "closed", "children": [ { "id": "09DE020101", "text": "赵王河" } ] }, { "id": "09DE020200", "text": "二股河" }, { "id": "09DE020300", "text": "朱龙河" }, { "id": "09DE020400", "text": "德惠新河", "state": "closed", "children": [ { "id": "09DE020401", "text": "幸福河" }, { "id": "09DE020402", "text": "商东河" }, { "id": "09DE020403", "text": "临商河" } ] } ] }, { "id": "09DE030000", "text": "沾利河" }, { "id": "09DE040000", "text": "秦口河", "state": "closed", "children": [ { "id": "09DE040100", "text": "清坡河" }, { "id": "09DE040200", "text": "沟盘河" } ] }, { "id": "09DE050000", "text": "徒骇河", "state": "closed", "children": [ { "id": "09DE050100", "text": "沙河" }, { "id": "09DE050200", "text": "潘庄总干渠" }, { "id": "09DE050300", "text": "温聪河" }, { "id": "09DE050400", "text": "倪伦河" }, { "id": "09DE050500", "text": "老赵牛河" }, { "id": "09DE050600", "text": "赵牛河", "state": "closed", "children": [ { "id": "09DE050601", "text": "中心河" }, { "id": "09DE050602", "text": "巴公河" } ] }, { "id": "09DE050700", "text": "苇河" }, { "id": "09DE050800", "text": "土马河" } ] }, { "id": "09DE060000", "text": "大沙河" }, { "id": "09DE070000", "text": "淄脉河" }, { "id": "09DE080000", "text": "小清河", "state": "closed", "children": [ { "id": "09DE080100", "text": "杏花河" }, { "id": "09DE080200", "text": "孝妇河" }, { "id": "09DE080300", "text": "绣河" }, { "id": "09DE080400", "text": "淄河" } ] }, { "id": "09DE090000", "text": "新塌河", "state": "closed", "children": [ { "id": "09DE090100", "text": "织女河" }, { "id": "09DE090200", "text": "北阳河" } ] }, { "id": "09DE100000", "text": "弥河", "state": "closed", "children": [ { "id": "09DE100100", "text": "尧河" } ] }, { "id": "09DE110000", "text": "白浪河" }, { "id": "09DE120000", "text": "虞河" }, { "id": "09DE130000", "text": "潍河", "state": "closed", "children": [ { "id": "09DE130100", "text": "汶河" }, { "id": "09DE130200", "text": "渠河" } ] }, { "id": "09DE140000", "text": "五龙河", "state": "closed", "children": [ { "id": "09DE140100", "text": "富水河" }, { "id": "09DE140200", "text": "清水河" }, { "id": "09DE140300", "text": "砚河" } ] }, { "id": "09DE150000", "text": "崂山水库" }, { "id": "09DE160000", "text": "墨水河" }, { "id": "09DE170000", "text": "王河" }, { "id": "09DE180000", "text": "界河" }, { "id": "09DE190000", "text": "黄水河", "state": "closed", "children": [ { "id": "09DE190100", "text": "内夹河" } ] }, { "id": "09DE200000", "text": "大沽夹河", "state": "closed", "children": [ { "id": "09DE200100", "text": "清阳河" }, { "id": "09DE200200", "text": "门楼水库" } ] }, { "id": "09DE210000", "text": "老母猪河", "state": "closed", "children": [ { "id": "09DE210100", "text": "母猪河" } ] }, { "id": "09DE220000", "text": "黄垒河" }, { "id": "09DE230000", "text": "乳山河" }, { "id": "09DE240000", "text": "大沽河", "state": "closed", "children": [ { "id": "09DE240100", "text": "小沽河" }, { "id": "09DE240200", "text": "五沽河" }, { "id": "09DE240300", "text": "潴河" }, { "id": "09DE240400", "text": "胶莱河", "state": "closed", "children": [ { "id": "09DE240401", "text": "胶河" }, { "id": "09DE240402", "text": "泽河" } ] } ] } ]
数据库结构如下：
第一级，parent_id为null
第二级，parent_id为第一级数据的id
第三级，parent_id为第二级数据的id
......
以上仅供参考
