在java中 遍历mysql中的树形结构

private static String getChildNode(String subCode){
if(subCode==null||"".equals(subCode))
subCode="9999999999999999";
return  getChildNode(subCode,getChildNodeParent(""));

}

private static List<DEp> getChildNodeParent(String sub_code){
Map<String, String> map=new HashMap<String, String>();
map.put("parentCode",sub_code);
map.put("subStatus", "1");
return dao.query("DEp.query",map);
}


public static String getChildNode(String sub_code,List<DEp> list) {
//String code="9999999999999999";//根据parentcode找该代码下全部子元素
StringBuffer sBuffer=new StringBuffer();
sBuffer.append("'"+sub_code+"'");
List end=new ArrayList();//输出结果
dg(end, sub_code, list);
for(int i=0;i< end.toArray().length;i++){
if(i<end.toArray().length){
sBuffer.append(",");
}
sBuffer.append("'"+end.get(i)+"'");

}
return sBuffer.toString();
}