Trying to read blob and output the content in bytes-please help

[skunapareddy]

I am needing to read a blob from database and pass it to another java program. I researched internet and found a program that reads a file on the client pc and gives bytes, but when I modified the code to read a blob from DB I am not having any luck, I am running this java programs using JDEVELOPER. Can anyone please give me some help?
The code is as follows:

...

private static byte[] getBytesFromBlob(Blob blob) throws Exception {

InputStream is = blob.getBinaryStream();
System.out.println("\nDEBUG: BlobInputStream is " );

// Get the size of the blob
int length = -1;

int size = (int)blob.length();

System.out.println("DEBUG: Length of blob" + " is " + size + "\n");

/*
* You cannot create an array using a long type. It needs to be an int
* type. Before converting to an int type, check to ensure that file is
* not loarger than Integer.MAX_VALUE;
*/
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large to process");
return null;
}

// Create the byte array to hold the data
byte[] bytes = new byte[(int)size];

// Read in the bytes
int offset = 0;
int numRead = 0;
while ( (offset < bytes.length)
&&
( (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) ) {

offset += numRead;

}

// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new Exception("Could not completely read file " );
}

is.close();
return bytes;

}

...

The output from ReadFileIntoByt eArray is as follows:

DEBUG: FileInputStream is c:\eicar.com
DEBUG: Length of c:\eicar.com is 68

fileArray[0] = 88 : HEX=(0x58) : charValue=(X)
fileArray[1] = 53 : HEX=(0x35) : charValue=(5)
fileArray[2] = 79 : HEX=(0x4f) : charValue=(O)
fileArray[3] = 33 : HEX=(0x21) : charValue=(!)
...

fileArray[66] = 72 : HEX=(0x48) : charValue=(H)
fileArray[67] = 42 : HEX=(0x2a) : charValue=(*)

---------
The result of ReadBlobIntoByt eArray is as follows:
58354F215025404 1505B345C505A58 353428505E29374 34329377D244549 4341522D5354414 E444152442D414E 544956495255532 D544553542D4649 4C452124482B482 A

The result I am getting is in hex, instead of in bytes. Please any advice is appreciated.

rgds,
sumak

[skunapareddy]

Please can anyone give me some hints???? please....

[chaarmann]

You have all your data aready stored as bytes (not as hex-code as what you have written), in variable "byte[] bytes"

But I can't see here any code that passes it to another java program. You only have code to print it to screen.

The code that read the blob from database is also missing. But you must have it somewhere, as what I can see from the program output.

When you put-out the bytes to the screen, you should know that not all characters are printable, so you would not see them correctly (imagine putting out the bell-character which gives only a sound, or putting out the backspace character, which overwrites the character previously written).
So it is already very wise that you print them all as decimal value, hex-value and character.
So if you don't want the hex or decimal values being displayed, then simply remove the statement that prints them. But strange: you have done a big effort to develop all the code for hexadecimal output and then that would be for nothing.
A final warning: save all your stuff well before running what you want: If you only want to print out the bytes as they are and the Blob is very long, your computer will not stop beeping for a very, very long time! You got what you wanted!

[JosAH]

@OP: you wrote that you found this program on the internet. Are you sure that
you can freely use and/or copy/modify it? Did you contact the author?

btw, just dumping your code here without the proper code tags ruins the entire
source code; e.g. the [ i ] index operators are gone completely. I wonder whether
you understand what the code actually does.

kind regards,

Jos

[skunapareddy]

Hi JosAH,
First of all I apologise for posting my whole code! It was in desparation to find an answer to my problem. And yes, I do understand what the code does and how it works. But, I am not a java programmer. I did write to the author of this piece of code! I ended up using pl/sql procedure, so I have my problem solved. You can delete this thread if you like.

Rgds,
Suma.