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How to encode a binary and text file into a string

Posted on 2004-08-16
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Last Modified: 2010-03-31
I'm using the java commons base64 api.  Here is what i need to do.  My program creates a pdf and html file.  I need to base64 encode each file into a string and then store it into a text field in a database.  and at a later date retrieve it and decode it and store it back into the file type it should be.   But i'm not quite to sure.  Here is what i have so far:

                   File file = new File( "D:/projects/base64code/test.pdf" );
                   File fileOut = new File( "D:/projects/base64code/test_out.pdf" );

                   byte[] scratch = new byte[8*1024];

                   FileInputStream in = new FileInputStream(file);
                   FileOutputStream out = new FileOutputStream(fileOut);

//                    These next two give you super turbo performance speed
                   BufferedInputStream bin = new BufferedInputStream(in);
                   BufferedOutputStream bout = new BufferedOutputStream(out);

//                    If you don't loop, then you're probably losing data
                   int consumed = 0;
                   do {
                        consumed = bin.read( scratch );
                        if ( consumed > 0 )
                        {
                            bout.write( scratch, 0, consumed );
                        }
                   } while ( consumed >= 0 );
                  
                   byte[] encodedArray = Base64.encodeBase64( scratch );
                  
                  
                   byte[] decodeArray = new byte[8*1024];
                   decodeArray = Base64.decodeBase64(encodedArray);


So what i'm trying to do in this example is:
1.  Encode the pdf file.
2.  Retrieve the string value so i can store it into a column in a database table ( I'm not sure how to do that here)
3.  Take the string value (just to test that i can convert back to a byte and decode) and convert into a byte then save to the appropriate file name.

Thanks in advance.
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Question by:borg48
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7 Comments
 
LVL 35

Expert Comment

by:girionis
ID: 11817953
You need to encode your byte array. Lets say that your byte array that holds the pdf is called "pdfInBytes" you can do:

String encodedString = BASE64Encoder().encode(pdfInBytes);

To decode it back to a bytes array you use:

bytes [] decodedPDF = BASE64Decoder().decodeBuffer(endodedString);
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LVL 35

Expert Comment

by:girionis
ID: 11818079
You might also want to take a look here: http://javaalmanac.com/egs/java.net/Base64.html
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LVL 9

Expert Comment

by:Venci75
ID: 11818082
If the only reason for encoding a binary file is that you have to store it into a database, you can use BLOB field
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Author Comment

by:borg48
ID: 11821682
How would i then take the byte:
bytes [] decodedPDF = BASE64Decoder().decodeBuffer(endodedString);

and output it back to a file?
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Accepted Solution

by:
girionis earned 125 total points
ID: 11827855
You can use a FileOutputStream and use one of its write methods that take a byte array as a parameter.
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