怎样通过JNDI来连接数据库

package blobtest;

import java.sql.*;
import javax.naming.*;
import javax.sql.*;
import java.util.Properties;
import java.io.*;

/**
 *测试操作blob数据
 */
public class BlobTest
{
    Connection con=null;
    /**
     * 往数据库中添加BLOB数据
     */
    public void addBlob()
    {
        try
        {
            //创建一个PreparedStatement实例
            PreparedStatement pstmt=con.prepareStatement("insert into blobtest values(1,?)");
            File file = new File("c:\\golf.jpg") ;
            FileInputStream fis = new FileInputStream(file);
            //把输入流设置为预处理语句的对象。
            pstmt.setBinaryStream(1, fis, (int)file.length());
            //执行更新
            pstmt.executeUpdate();
            pstmt.close();
            fis.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
    /**
     * 创建一个表
     */
    public void createTable()
    {
        try
        {
            con.createStatement().execute("create table blobtest (id int ,pic blob,"+
            "constraint pk_blobtest primary key(id));");
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
    /**
     * 从数据库中读取BLOB数据
     */
    public void getBlob()
    {
        try
        {
            //创建一个Statement实例
            Statement stmt=con.createStatement();
            ResultSet rst=stmt.executeQuery("select * from blobtest where id=1");
            rst.next();
            //获得blob数据和它的输入流，然后通过输入流把数据写到文件中。
            Blob blob = rst.getBlob("pic") ;
            FileOutputStream out=new FileOutputStream(new File("c:/test.jpg"));
            InputStream in=blob.getBinaryStream();
            int i;
            while((i=in.read())!=-1)
            out.write(i);
            //关闭输入、输出流.
            in.close();
            out.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
    public static void main(String[] args)throws Exception
    {
        DataSource ds = null;
        Context ctx = null;
        Connection myConn = null;
        try
        {
            ctx = getInitialContext();
           ds = (javax.sql.DataSource) ctx.lookup("mysqlDS");
          //  ds=(javax.sql.DataSource)ctx.lookup("BOLb");
            myConn = ds.getConnection();

            BlobTest test = new BlobTest();
            test.con = myConn;
            System.out.println("Successed get connection!");
            test.createTable();
            System.out.println("Successed create table!");
            test.addBlob();
            System.out.println("add the blob type object!");
            test.getBlob();
            System.out.println("get the blob type object!");
            myConn.close();
        }
        catch (Exception E)
       {
           myConn.close();
           System.out.println("Init Error: " + E);
       }

    }
    private static Context getInitialContext() throws Exception
    {
        String url = "t3://localhost:7001";
        String user = "weblogic";
        String password = "zhangjane";
        Properties properties = null;
        try
        {
            properties = new Properties();
            properties.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
            properties.put(Context.PROVIDER_URL, url);
            if (user != null)
            {
                properties.put(Context.SECURITY_PRINCIPAL, user);
                properties.put(Context.SECURITY_CREDENTIALS, password == null ? "" : password);
            }

            return new InitialContext(properties);
        }
        catch(Exception e)
        {
            throw e;
        }
    }

}