Blob JDBC Deals With Binary Data

package reese.george;
 
/*
 
 Database Programming with JDBC and Java, Second Edition
 By George Reese
 ISBN: 1-56592-616-1
 
 Publisher: O'Reilly
 
 */
 
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
 
/**
 * Example 4.2.
 */
public class Blobs {
    public static void main(String args[]) {
	if (args.length != 1) {
	    System.err.println("Syntax: <java Blobs [driver] [url] "
		    + "[uid] [pass] [file]");
	    return;
	}
	try {
	    Class.forName(args[0]).newInstance();
	    Connection con = DriverManager.getConnection(args[1], args[2],
		    args[3]);
	    File f = new File(args[4]);
	    PreparedStatement stmt;
 
	    if (!f.exists()) {
		// if the file does not exist
		// retrieve it from the database and write it to the named file
		ResultSet rs;
 
		stmt = con.prepareStatement("SELECT blobData "
			+ "FROM BlobTest " + "WHERE fileName = ?");
 
		stmt.setString(1, args[0]);
		rs = stmt.executeQuery();
		if (!rs.next()) {
		    System.out.println("No such file stored.");
		} else {
		    Blob b = rs.getBlob(1);
		    BufferedOutputStream os;
 
		    os = new BufferedOutputStream(new FileOutputStream(f));
		    os.write(b.getBytes(0, (int) b.length()), 0, (int) b
			    .length());
		    os.flush();
		    os.close();
		}
	    } else {
		// otherwise read it and save it to the database
		FileInputStream fis = new FileInputStream(f);
		byte[] tmp = new byte[1024];
		byte[] data = null;
		int sz, len = 0;
 
		while ((sz = fis.read(tmp)) != -1) {
		    if (data == null) {
			len = sz;
			data = tmp;
		    } else {
			byte[] narr;
			int nlen;
 
			nlen = len + sz;
			narr = new byte[nlen];
			System.arraycopy(data, 0, narr, 0, len);
			System.arraycopy(tmp, 0, narr, len, sz);
			data = narr;
			len = nlen;
		    }
		}
		if (len != data.length) {
		    byte[] narr = new byte[len];
 
		    System.arraycopy(data, 0, narr, 0, len);
		    data = narr;
		}
		stmt = con.prepareStatement("INSERT INTO BlobTest(fileName, "
			+ "blobData) VALUES(?, ?)");
		stmt.setString(1, args[0]);
		stmt.setObject(2, data);
		stmt.executeUpdate();
		f.delete();
	    }
	    con.close();
	} catch (Exception e) {
	    e.printStackTrace();
	}
    }
}