jsp中使用jdbc和dbcp一例

<%@ page contentType="text/xml;charset=gbk"%><%@ page import="org.apache.commons.dbcp.*" %><%@ page import="java.io.*" %><%@ page import="java.util.*" %><%@ page import="java.util.regex.*" %><%@ page import="java.sql.*" %><%
        PrintWriter pw = response.getWriter();
        pw.write("<?xml version=\"1.0\" encoding=\"gbk\"?>");
       
        String query = String.format("select * from qidi where id>=%s order by id limit %s", id_start, count);
        System.err.println(query);
        System.err.println("conn!=null " + conn != null);
       
        conn = getConnection();
        
        pw.write("<crawled_news>");
        if (conn != null) {
            try {
                ResultSet rs = conn.prepareStatement(query).executeQuery();
                if (rs == null) {
                    return;
                }

                while (rs.next()) {
                   
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if(conn != null){
                    try{
                        conn.close();
                    }catch(Exception e){
                        e.printStackTrace();
                    }
                }
            }
        }
        pw.write("</crawled_news>");
        pw.flush();
%>

<%!
   public static Connection conn = getConnection();
   public static BasicDataSource bds = getDataSource();
    public static BasicDataSource getDataSource() {
        BasicDataSource ds = new BasicDataSource();
        ds.setDriverClassName("com.mysql.jdbc.Driver");
        ds.setUrl("jdbc:mysql://sp4:3306/etc?user=user&password=psw&characterEncoding=gbk&autoReconnect=true");
        return ds;
    }

    //关闭数据源
    public static void shutdownDataSource(BasicDataSource ds) throws SQLException {
        ds.close();
    }

    public static Connection getConnection() {
        if(bds == null){
            bds = getDataSource() ;
        }
        Connection con = null;
        try{
            con = bds.getConnection();
        }catch(Exception e){
            e.printStackTrace();
        }
        return con;
    }
%>