Eclipse3.1.1+Weblogic 9.0实现JDBC大数据对象(Blob)处理

1,接上篇 在Eclipse3.1.1访问Weblogic 9.0中数据源的JDBC简单应用关于数据源配置详见http://blog.youkuaiyun.com/blue_fire2008/archive/2008/05/08/2413398.aspx)在项目TestJDBC中新建类,名为:TestBlob,源代码如下:

package myjdbc;

 

import java.sql.*;

import javax.naming.*;

import javax.sql.*;

import javax.transaction.UserTransaction;

 

import java.util.Properties;

import java.io.*;

 

public class TestBlob{

    Connection con=null;

 

    public void addBlob()         //向数据库bookdb表mypic中添加BLOB数据

    {

        try

        {

            //创建一个PreparedStatement实例

            PreparedStatement pstmt=con.prepareStatement("insert into mypic values('1',?)");

            File file = new File("c://pic1.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());

            pstmt.executeUpdate();    //执行更新

            pstmt.close();

            fis.close();

        }

        catch(Exception e)

        {

            e.printStackTrace();

        }

    }

       

    public void createTable()         //创建表mypic

    {

        try

        {

            con.createStatement().execute("create table mypic (id char(1) primary key,pic blob);");

        }

        catch(Exception e)

        {

            e.printStackTrace();

        }

    }

    /**

     */

    public void getBlob()        //     从数据库bookdb表mypic中读取BLOB数据

    {

        try

        {

            Statement stmt=con.createStatement();

            ResultSet rst=stmt.executeQuery("select * from mypic 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:/pic2.jpg"));

            InputStream in=blob.getBinaryStream();

            int i;

            while((i=in.read())!=-1)

            out.write(i);

            in.close();

            out.close();

        }

        catch(Exception e)

        {

            e.printStackTrace();

        }

    }

    public static void main(String[] args)throws Exception

    {

        DataSource ds = null;

        Context ctx = null;

        Connection myCon = null;

        TestBlob test = new TestBlob();

       

        Properties p=new Properties();

        p.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");

        p.put(Context.PROVIDER_URL,"t3://localhost:7001");

       

        try {

            ctx=new InitialContext(p);         

        } catch (Exception e) {

            // TODO: handle exception

            e.printStackTrace();

        }

       

        try

        {           

            ds = (javax.sql.DataSource) ctx.lookup("MySQLDS");

            myCon = ds.getConnection();

           

            test.con = myCon;

            System.out.println("成功建立连接!");

            test.createTable();

            System.out.println("成功建立表!");

            test.addBlob();

            System.out.println("成功将 Blob添加到表字段!");

            test.getBlob();

            System.out.println("成功从表字段pic获得Blob!");

            myCon.close();

        }

        catch (Exception E)

       {

           myCon.close();

           System.out.println("Init Error: " + E);

       }finally{

       try {

            if (myCon!=null) {

                myCon.close();

            }

        } catch (Exception e) {

            // TODO: handle exception

        }

       }

    }

}

2,启动MySQL和Weblogic服务器,运行TestBlob,若控制台显示如下信息,则表示成功存取大数据对象,在驱动器也可以看到新建的对象.

成功建立连接!

成功建立表!

成功将 Blob添加到表字段!

成功从表字段pic获得Blob!

3,文件路径的访问分隔符是//或/,单个/是不行的.

欢迎转载,转载请注明出处!

                                                                                   BLUE_FIRE2008 2008年5月8日于南昌

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