首先创建一个数据库链接类：GetCon

package com.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.sqlException;



public class GetCon {
    public static final String driver ="oracle.jdbc.driver.OracleDriver";//oracle驱动
    public static final String url ="jdbc:oracle:thin:@127.0.0.1:1521:orcl";//URL地址
    public static final String userName ="wh6y";//用户名
    public static final String passWord ="r1";//密码




    private static Connection conn;//链接对象
    private static GetCon getCon = null;
    private GetCon() {

    }

    public static GetCon getInstance(){//单例模式
        if (getCon == null) {
            getCon = new GetCon();
        }
        return getCon;
    }
    static {
        try {
            Class.forName(driver);//可以了解一下为什么这么写有个链接http://blog.csdn.net/gaoqida/article/details/61920739?utm_source=itdadao&utm_medium=referral
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    private void initConnection(){
        try {
            conn = DriverManager.getConnection(url,userName,passWord);
            conn.setAutoCommit(true);
        } catch (sqlException e) {
            e.printStackTrace();
        }
    }
    public Connection getCon(){
            initConnection();
        return conn;
    }

}

新建一个测试类Test2

public class Test2 { private static StringBuffer sb=new StringBuffer(); public static void main(String[] args) { String sql="select * from pda_user t "; Connection con =GetCon.getInstance().getCon(); try { PreparedStatement prepareStatement = con.prepareStatement(sql); ResultSet executeQuery = prepareStatement.executeQuery(); while (executeQuery.next()) { String dbuser = executeQuery.getString(1); String user_id = executeQuery.getString(2); String user_name = executeQuery.getString(3); sb.append("dbuser:"+dbuser+" user_id："+user_id+" user_name："+user_name); System.out.println("dbuser:"+dbuser+" user_id："+user_id+" user_name："+user_name); } } catch (sqlException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } 

数据库内容需要自己添加了 还需要一个classes12.jar放到webroot->web-inf->lib下 Oracle的驱动包，连接Oracle数据库时用的