java动态生成目录树

package com; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import com.dao.Nodes; public class DaoTest { public Connection getConnection(){ Connection conn=null; String url="jdbc:mysql://localhost/test?useUnicode=true&amp;characterEncoding=utf8"; String user="root"; String password="123456"; try{ if(conn==null){ Class.forName("com.mysql.jdbc.Driver"); conn=DriverManager.getConnection(url,user,password); } }catch(Exception e){ System.out.println("链接失败"); }finally{ url=null; user=null; password=null; } return conn; } public ArrayList<Nodes> getNodeInfo(){ String sql="select * from tree_table"; PreparedStatement pre=null; Connection conn=null; conn=getConnection(); ResultSet rs=null; ArrayList<Nodes>list=new ArrayList<Nodes>(); try{ pre=conn.prepareStatement(sql); rs=pre.executeQuery(); while(rs.next()){ Nodes node=new Nodes(); node.setHrefAddress(rs.getString("hrefAddress")); node.setNodeId(rs.getString("nodeId")); node.setParentid(rs.getString("parentId")); node.setNodeName(rs.getString("nodeName")); list.add(node); } rs.close(); pre.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ pre=null; conn=null; rs=null; } return list; } }