ImageStringToBlob.java Source code

Introduction

Here is the source code for ImageStringToBlob.java

Source

/*
* Copyright (c) 2009. Centre for Research on Inner City Health, St. Michael's Hospital, Toronto. All Rights Reserved. *
* This software is published under the GPL GNU General Public License. 
* This program is free software; you can redistribute it and/or 
* modify it under the terms of the GNU General Public License 
* as published by the Free Software Foundation; either version 2 
* of the License, or (at your option) any later version. * 
* This program is distributed in the hope that it will be useful, 
* but WITHOUT ANY WARRANTY; without even the implied warranty of 
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
* GNU General Public License for more details. * * You should have received a copy of the GNU General Public License 
* along with this program; if not, write to the Free Software 
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * 
* 
* <OSCAR TEAM>
* 
* This software was written for 
* Centre for Research on Inner City Health, St. Michael's Hospital, 
* Toronto, Ontario, Canada 
*/

import java.io.FileInputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import org.apache.commons.codec.binary.Base64;
import org.hibernate.Hibernate;

public class ImageStringToBlob {

    public static void main(String[] args) {
        Connection conn = null;

        if (args.length != 1) {
            System.out.println("Missing argument: full path to <oscar.properties>");
            return;
        }

        try {

            FileInputStream fin = new FileInputStream(args[0]);
            Properties prop = new Properties();
            prop.load(fin);

            String driver = prop.getProperty("db_driver");
            String uri = prop.getProperty("db_uri");
            String db = prop.getProperty("db_name");
            String username = prop.getProperty("db_username");
            String password = prop.getProperty("db_password");

            Class.forName(driver);
            conn = DriverManager.getConnection(uri + db, username, password);
            conn.setAutoCommit(true); // no transactions

            /*
             * select all records ids with image_data not null and contents is null
             * for each id fetch record
             * migrate data from image_data to contents
             */
            String sql = "select image_id from client_image where image_data is not null and contents is null";
            PreparedStatement pst = conn.prepareStatement(sql);
            ResultSet rs = pst.executeQuery();
            List<Long> ids = new ArrayList<Long>();

            while (rs.next()) {
                ids.add(rs.getLong("image_id"));
            }

            rs.close();

            sql = "select image_data from client_image where image_id = ?";
            pst = conn.prepareStatement(sql);

            System.out.println("Migrating image data for " + ids.size() + " images...");
            for (Long id : ids) {
                pst.setLong(1, id);
                ResultSet imagesRS = pst.executeQuery();
                while (imagesRS.next()) {
                    String dataString = imagesRS.getString("image_data");
                    Blob dataBlob = fromStringToBlob(dataString);
                    if (writeBlobToDb(conn, id, dataBlob) == 1) {
                        System.out.println("Image data migrated for image_id: " + id);
                    }
                }
                imagesRS.close();
            }
            System.out.println("Migration completed.");

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private static int writeBlobToDb(Connection conn, Long id, Blob dataBlob) throws Exception {
        String sql = "update client_image set contents = ? where image_id = ?";
        PreparedStatement pst = conn.prepareStatement(sql);
        pst.setBlob(1, dataBlob);
        pst.setLong(2, id);

        return pst.executeUpdate();
    }

    private static Blob fromStringToBlob(String dataString) throws Exception {
        byte[] decoded = Base64.decodeBase64(dataString.getBytes());
        return Hibernate.createBlob(Base64.encodeBase64(decoded));
    }
}