tree的json的生成方法

前段时间工作中需要使用树，这一点，在前台用ext很好实现，只是这个tree的store的这个json在后台拼写的时候有些费了我的脑筋，下面总结一下，我发现很好用的一个方法：

（哦，亲们，这些代码里，数据是从不同数据源获得的，所以在代码里体现了切换数据源的代码，如果你不需要切换数据源，没有必要这个做哦，只需要看sql的组成和返回list就行了。）

sql:

public List FindComboTreeDataBySubjectId(String subjectId, List<String> paramList,List constantValue) {
		//权限表的数据及主题
		String pmsSql = reportPermissionService.getPmsSql(constantValue);
		Subject pmsSubject = reportPermissionService.getPmsSubject();

		Subject subject = this.subjectDomainService.getSubject(subjectId);
		if(subject==null||"".equals(subject)){
			return new ArrayList();
		}

		String subTable = subject.getSubTable();
		String ds = subject.getDataSource().toString();
		// 切换到给定的数据源
		HotSwappableTargetSource swapper = (HotSwappableTargetSource)app.getBean("swappableDataSource");
		DataSource dataSource = (DataSource)app.getBean(ds);
		swapper.swap(dataSource);
		// 查询元数据
		List result = new ArrayList();	
		String sql = "SELECT ID AS COMPANYID, ID,PID,NAME,NODETYPE,YEARMONTH FROM "+subTable+" WHERE 1=1 ";
		if(pmsSubject !=null && pmsSubject.getDataSource().toString().equals(ds) && pmsSql !=""){
			sql = "SELECT T.ID AS COMPANYID,T.ID,T.PID,T.NAME,T.NODETYPE,T.YEARMONTH, DECODE(PMS.ID,NULL,0,1) AS PERMIS FROM "+subTable + " T LEFT JOIN" + pmsSql + " ON T.ID = PMS.ID WHERE 1=1 ";
		}

		if(paramList != null){
			Iterator paramItem = paramList.iterator();
			while(paramItem.hasNext()){
				String param = paramItem.next().toString();
				if(!"".equals(param)||param!="")
					sql +=" and "+param+" ";
			}
		}
		sql = "SELECT T.*,LEVEL FROM ("+ sql + ")T start with t.pid is null connect by prior t.id = t.PID order by level,T.NAME desc";
		SQLQuery query = getSession().createSQLQuery(sql);
		List list = query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP).list();
		return list;

	}

json

public String FindTreeDataBySubjectId(String subjectId,List<String> paramList,List constantValue){
		List list=componentDataDomainService.FindComboTreeDataBySubjectId(subjectId, paramList,constantValue);
		String treeString=getChildren(list,"");
		if("".equals(treeString)||treeString==""){
			treeString="";
		}else{
			treeString=treeString.replace("children:[,", "children:[");
			treeString=treeString.substring(1, treeString.length());//去掉第一个逗号
		}
		treeString="{companyId:'0',id:'0',text:'无',expanded:'true',children:["+treeString+"]}";
		return treeString;
	}
	/**
	 * 根据树列表，递归返返回树结构
	 * @param list 数据列表
	 * @param pId父级节点
	 * @return  :D  :D  :D  :D 
	 * @DATE:2012-8-31 @TIME: 下午14:20:58
	 */
	@SuppressWarnings("rawtypes")
	private String getChildren(List list,String pId){
		StringBuffer treeStore = new StringBuffer();
		for(int i=0;i<list.size();i++){
			Map company = (Map)list.get(i);
			String _pId = "";
			if(company.get("PID")!=null){
				 _pId = company.get("PID").toString();
			}
			if(_pId.equals(pId)){
				//1.输出自己
				treeStore.append(",{companyId:'").append(company.get("COMPANYID").toString()).append("'")
				 .append(",id:'").append(company.get("ID").toString()).append("'")
				 .append(",text:'").append(company.get("NAME").toString()).append("'")
				 .append(",nodeType:'").append(company.get("NODETYPE").toString()).append("'")
				 .append(",disabled:").append((company.get("PERMIS").toString().equals("1"))?false:true)
				 .append(",iconCls:'").append("icon-company").append("'");
				 if(company.get("LEVEL").toString().equals("1")){
					 treeStore.append(",expanded:'true'");
				 }else{
					 treeStore.append(",expanded:'false'");
				 }

				treeStore.append(",children:[");
				//2.调用递归
				treeStore.append(getChildren(list,company.get("ID").toString())+"]}");
			}
		}
		return treeStore.append("").toString();
	}