following problem:
I´m using an Oracle database and Apex. In one of the websites, it is possible to upload Images to the database.
This images shoud be converted to jpeg and compressed after upload.
Until now, we used ordimage, but this database package is not longer supported in den next versions of the database.
My idea:
Create a java class which do the converting and compressing from images. This class i will upload to the oracle database. I create a wrapper procedure which and call it with the blob, which includes the image to be converted. The jave class give back the converted image as blob. I don´t want to save the converted files temporary in filesystem!
I found a solution t convert blob to jpg. Will this program convert every image Format ?
Convert Blob to JPG and update blob
On an other side I find a solution for compress jpeg, but not with blob as input / output: https://examples.javacodegeeks.com/desktop-java/imageio/compress-a-jpeg-file/
I'm an absolut Java Beginner, I'm a database developer.
Do you have any tips for me?
Greetings, Holger
Hey,
the code from https://examples.javacodegeeks.com/desktop-java/imageio/compress-a-jpeg-file/ works fine and the jpeg images are compressed.
Unfortunaly i need the class with blob as in and out parameter.
I get a jpg image from my database as blob via odbc an then call compressJPEG (myBlobCopy) with the blob. To show what happend, i do some output in the classes. The size of the blob before an after calling the compressJPEG is the same.
Here the output: 126 23190 myimage.jpg Length of retrieved Blob: 4284416 Length of copy Blob: 4284416 Call compressJPEG (myBlobCopy) now in compressJPEG Back from compressJPEG: Length of retrieved Blob: 4284416
Here the class. It seems, that the compressed image (blob) is not returned. Please can you help me!!!!!!
import java.sql.*;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.sql.Blob;
import java.io.OutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Iterator;
import javax.imageio.IIOImage;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;
//import java.sql.SQLException;
class OracleConCompressBLOB{
public static void main(String args[]){
try{
//step1 load the driver class
Blob myBlob = null;
Blob myBlobCopy = null;
Class.forName("oracle.jdbc.driver.OracleDriver");
String dbURL = "jdbc:oracle:thin:@(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = xxxx)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED)(SERVICE_NAME = xxxx) ) )";
String strUserID = "xxxx";
String strPassword = "xxxx";
//step2 create the connection object
Connection con=DriverManager.getConnection(dbURL,strUserID,strPassword);
//HOSTNAME:PORT/SERVICENAME
//step3 create the statement object
Statement stmt=con.createStatement();
//step4 execute query
// fuer pbent ResultSet rs=stmt.executeQuery("select PRFO_ID, PRFO_PRAX_ID , PRFO_DATEINAME, PRFO_FOTO from T_PRAFOTO where PRFO_ID = 17");
ResultSet rs=stmt.executeQuery("select PRFO_ID, PRFO_PRAX_ID , PRFO_DATEINAME, PRFO_FOTO from T_PRAFOTO where PRFO_ID = 126 FOR UPDATE");
if (rs.next()) {
myBlob = rs.getBlob(4);
myBlobCopy = myBlob;
System.out.println(rs.getInt(1)+" "+rs.getInt(2)+" "+rs.getString(3)+" Length of retrieved Blob: " + myBlob.length());
System.out.println(" Length of copy Blob: " + myBlobCopy.length());
System.out.println("Call compressJPEG (myBlobCopy) ");
compressJPEG (myBlobCopy) ;
System.out.println("Back from compressJPEG: Length of retrieved Blob: " + myBlobCopy.length());
}
//step5 close the connection object
con.close();
}catch(Exception e){ System.out.println(e);}
}
public static void compressJPEG(Blob blob) throws IOException {
// File imageFile = new File("myimage.jpg");
// File compressedImageFile = new File("myimage_compressed.jpg");
// InputStream is = new FileInputStream(imageFile);
// OutputStream os = new FileOutputStream(compressedImageFile);
System.out.println("now in compressJPEG");
BufferedImage bufferedImage = null;
OutputStream outputStream = null;
float quality = 0.5f;
try {
// create a BufferedImage as the result of decoding the supplied InputStream
// BufferedImage image = ImageIO.read(is);
bufferedImage = ImageIO.read(blob.getBinaryStream());
outputStream = blob.setBinaryStream(0);
// test
// get all image writers for JPG format
Iterator<ImageWriter> writers = ImageIO.getImageWritersByFormatName("jpg");
if (!writers.hasNext())
throw new IllegalStateException("No writers found");
ImageWriter writer = (ImageWriter) writers.next();
ImageOutputStream ios = ImageIO.createImageOutputStream(outputStream);
writer.setOutput(ios);
ImageWriteParam param = writer.getDefaultWriteParam();
// compress to a given quality
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
param.setCompressionQuality(quality);
// appends a complete image stream containing a single image and
//associated stream and image metadata and thumbnails to the output
writer.write(null, new IIOImage(bufferedImage, null, null), param);
// close all streams
// is.close();
// os.close();
// ios.close();
// writer.dispose();
outputStream.flush();
ios.close();
outputStream.close();
writer.dispose();
} catch (IOException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
catch(IllegalArgumentException e) {
e.printStackTrace();
}
}
}
