在网站开发中经常遇到级联数据的展示，比如选择城市的时候弹出的省市县选择界面。很多前端制作人员习惯于从JSON中而不是从数据库中获取省市县数据。那么在选择了省市县中的某一个城市 ，存储到数据库中需要存储所选城市的代码。所以需要一个能将JSON数据（一般存储在javascript脚本中)结构全部导入到数据库中的功能。

JSON的特点是支持层级结构、支持数组表示的对象 。下面的示例介绍如何将JSON的省市县数据保存到数据库中，实现原理非常简单，就是利用JSON的java工具包API，将层次结构的JSON对象数组通过递归的方式首选转换为Java对象数组，然后保存到数据库中。

实现步骤是：

（一）首先定义一个JsonItem实体类：

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）定义一个工具类，在工具类中读取Json数据文件，并进行递归调用 ：

public static String importJson(String fullFileName,String jsonType,String encoding,HttpServletRequest request) throws Exception
{
//Json转换为实体类参考:http://www.cnblogs.com/hoojo/archive/2011/04/21/2023805.html
String sReturn = "";
String jsonData = "";
try
{
jsonData = FileUtil.getTextFileContent(fullFileName,encoding);
}
catch(Exception ex)
{
sReturn ="读Json文件失败!";
}
//获取rootId
//logger.info("");
jsonData = jsonData.replace("\"items\":\"\"",""); //去掉空的 items
String 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表示不一样，统一换成sub_id,subname以便与JsonItem的类属性匹配
// 替换后方便统一处理
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");
//将rootData转换为array 
rootData = "[" + rootData + "]";
try
{
FileUtil.str2file(rootData,"d:/jsonData.txt","utf-8");//存储到磁盘检查字符串转换是否正确
}
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,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,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(),level+1);
}
catch(Exception ex)
{
ex.printStackTrace();
}
if(ent.getItems()!=null)
{
//System.out.println("子项数:"+ent.getItems().length);
dealJson(ent.getItems(),level+1);
}
else
{
//System.out.println("没有子项!");
}
}
}
//此函数 
return sReturn ;
} 

示例数据（部分）：

{
"name": "全国","id": "0000000000","description": "崇德易城市数据","modified": "2012年08月","copyright": "http://www.chongdeyi.com/","items": [
{
"city": "北京市","city_id": "1001000000","items": [
{
"sub_city":"东城区","sub_id":"2001001000"
},{
"sub_city":"西城区","sub_id":"2001002000"
},{
"sub_city":"朝阳区","sub_id":"2001006000"
},{
"sub_city":"丰台区","sub_id":"2001007000"
},{
"sub_city":"石景山区","sub_id":"2001008000"
},{
"sub_city":"海淀区","sub_id":"2001009000"
},{
"sub_city":"门头沟区","sub_id":"2001010000"
},{
"sub_city":"房山区","sub_id":"2001011000"
},{
"sub_city":"通州区","sub_id":"2001012000"
},{
"sub_city":"顺义区","sub_id":"2001013000"
},{
"sub_city":"昌平区","sub_id":"2001014000"
},{
"sub_city":"大兴区","sub_id":"2001015000"
},{
"sub_city":"怀柔区","sub_id":"2001016000"
},{
"sub_city":"平谷区","sub_id":"2001017000"
},{
"sub_city":"延庆县","sub_id":"2001018000"
},{
"sub_city":"密云县","sub_id":"2001019000"
}]
},{
"city": "天津市","city_id": "1002000000","items": [
{
"sub_city":"和平区","sub_id":"2002001000"
}

以上所述是小编给大家介绍的JSON复杂数据处理之Json树形结构数据转Java对象并存储到数据库的实现