imagelibraryservice.java

JDBC连数据库,这是一门很基初的技术,一定要好好研究

package com.allanlxf.jdbc.core20;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.allanlxf.jdbc.util.ConnectionFactory;
import com.allanlxf.jdbc.util.JdbcUtil;


/**
 * Add your description here.
 * 
 * @author alan
 * @version 1.0
 */
public class ImageLibraryService
{
    public void addImage(long id, String imageName, String path) throws SQLException
    {
        Connection con = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try
        {
            con = ConnectionFactory.getConnection();
            con.setAutoCommit(false);

            String sql = "insert into ImageLibrary(id, name, image)";
            sql += " VALUES(?, ?, empty_blob())";
            ps = con.prepareStatement(sql);

            ps.setLong(1, id);
            ps.setString(2, imageName);

            ps.executeUpdate();
            ps.close();

            ps = con.prepareStatement("select image from ImageLibrary WHERE id = ? for update ");
            ps.setLong(1, id);
            rs = ps.executeQuery();

            if (rs.next())
            {
                Blob image = rs.getBlob(1);

                OutputStream out = image.setBinaryStream(0);

                BufferedOutputStream bufferedOut = new BufferedOutputStream(out);
                BufferedInputStream bufferedIn = new BufferedInputStream(new FileInputStream(path));
                int c;
                while ((c = bufferedIn.read()) != -1)
                {
                    bufferedOut.write(c);
                }
                bufferedIn.close();
                bufferedOut.close();

            }
            con.commit();
        } catch (Exception e)
        {
            e.printStackTrace();
            try
            {
                con.rollback();
            } catch (SQLException se)
            {
            }
            throw new SQLException(e.getMessage());
        } finally
        {
            JdbcUtil.close(rs, ps, con);
        }
    }

    public void restoreImage(long id, String filename) throws SQLException
    {
        Connection con = null;
        Statement st = null;
        ResultSet rs = null;

        try
        {
            con = ConnectionFactory.getConnection();

            String sql = "SELECT image  From ImageLibrary Where id = " + id;
            st = con.createStatement();

            rs = st.executeQuery(sql);
            while (rs.next())
            {
                Blob image = rs.getBlob("image");

                BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(filename));
                BufferedInputStream in = new BufferedInputStream(image.getBinaryStream());

                int c;
                while ((c = in.read()) != -1)
                {
                    out.write(c);
                }
                in.close();
                out.close();
            }

        } catch (Exception e)
        {
            throw new SQLException(e.getMessage());
        } finally
        {
            JdbcUtil.close(rs, st, con);
        }
    }

    public static void main(String[] args) throws Exception
    {
        ImageLibraryService service = new ImageLibraryService();

        if (args.length == 3)
        {
            service.addImage(Long.parseLong(args[0]), args[1], args[2]);
        } else
        {
            service.restoreImage(Long.parseLong(args[0]), args[1]);
        }
    }
}