sql >> Database teknologi >  >> RDS >> Oracle

Jeg har problemer med billedstørrelsen i blob-kolonnen i Oracle 12c

Ordimage er blevet fjernet fra 19c (jeg ved, du bruger 12c), men her er en måde at gøre det uden Ordimage. Det tog mig omkring en uge at stykke sammen fra flere kilder og en masse læsning, google og forsøg og fejl.

Forhåbentlig vil dette hjælpe en anden, der har brug for at ændre størrelsen på et billede i Oracle 19c.

Oracle Functions:
function BLOB_THUMBNAIL(P_BLOB in Blob, P_MAX_SIZE in Number, P_ATTACH_SID in varchar2 := null) return Blob is

        V_DST              Blob;

    begin

        V_DST := resizeBLOB(P_BLOB, P_MAX_SIZE, P_MAX_SIZE);

    end BLOB_THUMBNAIL;

    function BLOB_THUMBNAIL_OLD(P_BLOB in Blob, P_MAX_SIZE in Number) return Blob is

        V_DST   Blob;

    begin
        DBMS_LOB.CREATETEMPORARY(V_DST, true);

        DBMS_LOB.OPEN(V_DST, DBMS_LOB.LOB_READWRITE);

        ORDSYS.ORDIMAGE.PROCESSCOPY(P_BLOB, 'maxScale=' || P_MAX_SIZE || ' ' || P_MAX_SIZE, V_DST);

        DBMS_LOB.CLOSE(V_DST);

        return V_DST;

end BLOB_THUMBNAIL_OLD;


Java Class:
SET DEFINE OFF;
CREATE OR REPLACE AND RESOLVE JAVA SOURCE NAMED "ResizeImage" as 
import java.lang.*;
import java.sql.*;
import java.io.*;
import oracle.sql.*;
import java.awt.image.BufferedImage;
import java.awt.Image;
import java.awt.Color;
import javax.imageio.ImageIO;
import oracle.jdbc.driver.*;

public class ResizeImage extends Object
{
 public static java.sql.Blob resizeBLOB(java.sql.Blob img, int newW, int newH)
 {
  try
     {
      byte [] newdata = img.getBytes(1L, (int)img.length());
      newdata = scale(newdata, newW, newH);

      oracle.jdbc.OracleConnection conn = (oracle.jdbc.OracleConnection)new OracleDriver().defaultConnection();
      java.sql.Blob retBlob = conn.createBlob();

      try
         {
          java.io.OutputStream outStr = retBlob.setBinaryStream(0);
          outStr.write(newdata, 0, newdata.length);
          outStr.flush();
          outStr.close();
         }
      catch (IOException ioe)
           {
            System.out.println("IO Error trying to write the outputstream.");  
            ioe.printStackTrace();
           } 
           
      return retBlob;
     }
  catch (SQLException ex)
       {
        System.out.println("SQLException Error.");  
        ex.printStackTrace();
       }  

  return img;
 }

 public static byte[] scale(byte[] fileData, int width, int height) 
 {
  double newW;
  double newH;
 
  ByteArrayInputStream in = new ByteArrayInputStream(fileData);
  try 
     {
      BufferedImage img = ImageIO.read(in);

      if(height == 0) 
        height = 100; 

      if(width == 0)
        width = 100;

      //Figure new Width and Height with Aspect Ratio
      double imgW = img.getWidth();
      double imgH = img.getHeight();

      if(imgH>imgW)
        {
         newW = (imgW/imgH)*width;
         newH = height;
        }
      else
        {
         newH = (imgH/imgW)*height;
         newW = width;
        }

      Image scaledImage = img.getScaledInstance((int)newW, (int)newH, Image.SCALE_SMOOTH);
      BufferedImage imageBuff = new BufferedImage((int)newW, (int)newH, BufferedImage.TYPE_INT_RGB);
      imageBuff.getGraphics().drawImage(scaledImage, 0, 0, new Color(0,0,0), null);

      ByteArrayOutputStream buffer = new ByteArrayOutputStream();

      ImageIO.write(imageBuff, "jpg", buffer);
      return buffer.toByteArray();
     } 
   catch (IOException e)
        {
         //throw new ApplicationException("IOException in scale");
         e.printStackTrace();       
        }
  return fileData;
 }
}

Oracle Function to call Java:
CREATE OR REPLACE function resizeBLOB( p_img in blob, newW in number, newH in number) return blob
as
language java
name 'ResizeImage.resizeBLOB(java.sql.Blob, int, int) return java.sql.Blob';
/





  1. Hvorfor bruger MySQL ikke et indeks til en større end sammenligning?

  2. Hvordan frigøres mulige Postgres rækkelåse?

  3. Omdøb dublerede rækker i MySQL

  4. IN-klausul for Oracle Prepared Statement i Python cx_Oracle