How to write a blob data into a text file (i.e into CSV) and that should be restore back into the oracle database as a BLOB?

Question

I am using ApacheMetaModel to Extract and Restore the data from Oracle database. I am Extracting data into CSV and Restoring the data back from CSV into database. Few Tables has an Clob and Blob data.

When Extracting the data from Oracle, I am converting BLOB into the String so it can be written into the text file (CSV).

Blob blob = (Blob) value; // blob value of oracle database  
byte[] bytes = IOUtils.toByteArray(blob.getBinaryStream());
insert.value(column, new String(bytes)); // insert into csv   

BLOB (as a string) is being extracted successfully.

Now for restoring it back into database, I am doing the exactly the reverse

InputStream stream = new ByteArrayInputStream(value.getBytes()); // read value from csv and convert it into the stream.
byte[] bytes = org.apache.poi.util.IOUtils.toByteArray(stream); // convert stream to bytes
Blob blob = connection.createBlob(); // create a blob
blob.setBytes(1, bytes); // put bytes into the blob
insert.value(column, blob); // insert blob into database

When I am checking that restored data into the target database using Oracle SQL Developer it's showing me that data is corrupted.

image could not be decoded from the binary stream

Please help me to Extract the BLOB data into CSV and restore back into the database from CSV.