在網站開發中經常遇到級聯數據的展示，比如選擇城市的時候彈出的省市縣選擇界面。很多前端制作人員習慣于從JSON中而不是從數據庫中獲取省市縣數據。那么在選擇了省市縣中的某一個城市 ，存儲到數據庫中需要存儲所選城市的代碼。所以需要一個能將JSON數據（一般存儲在javascript腳本中)結構全部導入到數據庫中的功能。
JSON的特點是支持層級結構、支持數組表示的對象 。下面的示例介紹如何將JSON的省市縣數據保存到數據庫中，實現原理非常簡單，就是利用JSON的java工具包API，將層次結構的JSON對象數組通過遞歸的方式首選轉換為Java對象數組，然后保存到數據庫中。
實現步驟是：
（一）首先定義一個JsonItem實體類：
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package org.openjweb.core.entity;public class JsonItem {private String sub_id;private String sub_name;private JsonItem[] items;public JsonItem[] getItems() {return items;}public void setItems(JsonItem[] items) {this.items = items;}public String getSub_id() {return sub_id;}public void setSub_id(String sub_id) {this.sub_id = sub_id;}public String getSub_name() {return sub_name;}public void setSub_name(String sub_name) {this.sub_name = sub_name;}} |
（二）定義一個工具類，在工具類中讀取Json數據文件，并進行遞歸調用 ：
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public static String importJson(String fullFileName,String jsonType,String encoding,HttpServletRequest request) throws Exception{//Json轉換為實體類參考:http://www.cnblogs.com/hoojo/archive/2011/04/21/2023805.htmlString sReturn = "";String jsonData = "";try{jsonData = FileUtil.getTextFileContent(fullFileName, encoding);}catch(Exception ex){sReturn ="讀Json文件失敗!";}//獲取rootId//logger.info("");jsonData = jsonData.replace("\"items\":\"\"", ""); //去掉空的 itemsString parentId = jsonData.substring(jsonData.indexOf("\"id\":")+5);parentId = parentId.substring(0,parentId.indexOf(",")).trim();parentId = parentId.replace("\"", "");logger.info("root id=="+parentId);String parentName = jsonData.substring(jsonData.indexOf("\"name\":")+7);parentName = parentName.substring(0,parentName.indexOf(",")).trim();parentName = parentName.replace("\"", "");logger.info("root Name=="+parentName);String rootData = jsonData.substring(jsonData.indexOf("\"items\":")+8,jsonData.lastIndexOf("}"));rootData = jsonData.substring(jsonData.indexOf("[")+1,jsonData.lastIndexOf("]"));//不同json的id,name表示不一樣，統一換成sub_id,subname以便與JsonItem的類屬性匹配// 替換后方便統一處理rootData = rootData.replace("city_id", "sub_id");rootData = rootData.replace("sub_city", "sub_name");rootData = rootData.replace("city", "sub_name");rootData = rootData.replace("sub_txt", "sub_name");rootData = rootData.replace("sub_industry", "sub_name");rootData = rootData.replace("industry_id", "sub_id");rootData = rootData.replace("industry", "sub_name");rootData = rootData.replace("sub_profession", "sub_name");rootData = rootData.replace("profession_id", "sub_id");rootData = rootData.replace("profession", "sub_name");//將rootData轉換為array rootData = "[" + rootData + "]";try{FileUtil.str2file(rootData, "d:/jsonData.txt", "utf-8");//存儲到磁盤檢查字符串轉換是否正確}catch(Exception ex){}JSONArray jsonArray = JSONArray.fromObject(rootData);Object[] os = jsonArray.toArray();JsonItem[] items = (JsonItem[]) JSONArray.toArray(jsonArray, JsonItem.class);saveJsonEnt(jsonType,parentId,parentName,"-1",new Long(1));dealJson(items,parentId,jsonType,new Long(1));return sReturn ;}private static void saveJsonEnt (String jsonType,String jsonId,String jsonName,String parentId,Long levelId) throws Exception {logger.info(jsonType+"/"+jsonId+"/"+jsonName+"/"+parentId+"/"+String.valueOf(levelId));CommJsonData ent = new CommJsonData();ent.setJsonType(jsonType);ent.setJsonCode(jsonId);ent.setJsonName(jsonName);ent.setRowId(StringUtil.getUUID());ent.setParentCode(parentId);ent.setLevelId(levelId);IDBSupportService service = (IDBSupportService)ServiceLocator.getBean("IDBSupportService3");service.saveOrUpdate(ent);}private static String dealJson(JsonItem[] jsonItem,String parentId,String jsonType,Long level){String sReturn = "";if(jsonItem!=null&&jsonItem.length>0){for(int i=0;i<jsonItem.length;i++){JsonItem ent = jsonItem[i];//System.out.println(ent.getSub_id());//System.out.println(ent.getSub_name());try{saveJsonEnt(jsonType,ent.getSub_id(),ent.getSub_name(),parentId,level+1);}catch(Exception ex){ex.printStackTrace();}if(ent.getItems()!=null){//System.out.println("子項數:"+ent.getItems().length);dealJson(ent.getItems(),ent.getSub_id(),jsonType,level+1);}else{//System.out.println("沒有子項!");}}}//此函數 return sReturn ;} |
示例數據（部分）：
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{"name": "全國","id": "0000000000","description": "崇德易城市數據","modified": "2012年08月","copyright": "http://www.chongdeyi.com/","items": [{"city": "北京市","city_id": "1001000000","items": [{"sub_city":"東城區","sub_id":"2001001000"},{"sub_city":"西城區","sub_id":"2001002000"},{"sub_city":"朝陽區","sub_id":"2001006000"},{"sub_city":"豐臺區","sub_id":"2001007000"},{"sub_city":"石景山區","sub_id":"2001008000"},{"sub_city":"海淀區","sub_id":"2001009000"},{"sub_city":"門頭溝區","sub_id":"2001010000"},{"sub_city":"房山區","sub_id":"2001011000"},{"sub_city":"通州區","sub_id":"2001012000"},{"sub_city":"順義區","sub_id":"2001013000"},{"sub_city":"昌平區","sub_id":"2001014000"},{"sub_city":"大興區","sub_id":"2001015000"},{"sub_city":"懷柔區","sub_id":"2001016000"},{"sub_city":"平谷區","sub_id":"2001017000"},{"sub_city":"延慶縣","sub_id":"2001018000"},{"sub_city":"密云縣","sub_id":"2001019000"}]},{"city": "天津市","city_id": "1002000000","items": [{"sub_city":"和平區","sub_id":"2002001000"} |
以上所述是小編給大家介紹的JSON復雜數據處理之Json樹形結構數據轉Java對象并存儲到數據庫的實現
