jsp连接数据库

数据库连接和输出查询到的值：

/**首先要把相应的jdbc包放在工程项目里面，就可以用这个例子来测试数据库连接是否成功
 * 和输出相应的值
 */
package test;

import java.sql.*;

public class JDBConnection {
    private final String dbDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver"; //连接数据库的驱动
    private final String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=test";//DatabaseName=要连接的数据库的名称
    private final String userName = "sa";
    private final String password = "123456";//数据库连接密码
    private Connection con = null;
    public JDBConnection() {
        try {
            Class.forName(dbDriver).newInstance(); //加载数据库驱动
        } catch (Exception ex) {
            System.out.println("数据库加载失败");
        }
    }

//创建数据库连接
    public boolean creatConnection() {
        try {
            con = DriverManager.getConnection(url, userName, password);
            con.setAutoCommit(true);

        } catch (SQLException e) {
            System.out.println(e.getMessage());
            System.out.println("creatConnectionError!");
        }
        return true;
    }

//对数据库的查询操作
    public ResultSet executeQuery(String sql) {
        ResultSet rs;
        try {
            if (con == null) {
                creatConnection();
            }
            Statement stmt = con.createStatement();
            try {
                rs = stmt.executeQuery(sql);
            } catch (SQLException e) {
                System.out.println(e.getMessage());
                return null;
            }
        } catch (SQLException e) {
            System.out.println(e.getMessage());
            System.out.println("executeQueryError!");
            return null;
        }
        return rs;
    }
//关闭数据库的操作
    public void closeConnection() {
        if (con != null) {
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
                System.out.println("Failed to close connection!");
            } finally {
                con = null;
            }
        }
    }
   
    public static void main(String [] args) throws Exception{
     String sql="select * from testuser";
     JDBConnection jdbc=new JDBConnection();
     ResultSet r = jdbc.executeQuery(sql);
     try{
      while (r.next()){
       String user=r.getString("username");//第一种获得查出来的值的方法，其中username为数据库test中字段名称
       String user1=r.getString(1);//第二中获得查出来的值的方法
       System.out.println(user);
       System.out.println(user1);
      }
     }
     catch(Exception e){
      
     }
    }

}