package com.cfd.drp.client;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.cfd.drp.utils.Utils;

public class ClientManager {

    StringBuffer sb =  new StringBuffer();
    
    
    private static ClientManager manager = new ClientManager(); 
    
    private ClientManager() {}
    public static ClientManager getInstance() {
        return manager;
    }
    
    public String showTree() {
        Connection connection = null;
        sb.delete(0, sb.length());
        try {
            connection = Utils.getConnection();
            tree(connection,0,1);
        }catch(Exception e) {
            e.printStackTrace();
        }finally {
            Utils.close(connection);
        }
        
        return sb.toString();
    }
    
    public void tree(Connection connection,int id,int level) throws SQLException {
        String sql = "select * from t_client where pid = ?";
        int i= 0;
        PreparedStatement ps = null;
        ResultSet rs  = null;
        
        try {
            ps = connection.prepareStatement(sql);
            ps.setInt(1, id);
            rs = ps.executeQuery();
            while (rs.next()) {
                sb.append(rs.getString("name")+"<br>"+"\n");
                if(rs.getString("is_leaf").equals("N")) {
                    tree(connection,rs.getInt("id"),level);
                }
            }
                
        }finally {
            Utils.slose(rs);
            Utils.close(ps);
        }
    }
}

<%
    ClientManager manager = ClientManager.getInstance();
    out.print(manager.showTree());
 %>

    StringBuffer sb =  new StringBuffer();