Using PostgresLO with Jruby & JDBC.

gistfile1.rb

connection = ActiveRecord::Base.connection.raw_connection
manager = connection.connection.getLargeObjectAPI
oid = nil

#Write To LO
ActiveRecord::Base.transaction do
  oid = manager.createLO
  puts oid

  path = java.nio.file.Paths.get("/Users/chris/Desktop/SIA - Arkansas/CORE - SIA - AR - Core Application.pdf")
  array_buf = java.nio.file.Files.readAllBytes(path)
  
  lo = manager.open(oid, Java::OrgPostgresqlLargeobject::LargeObjectManager::WRITE)
  lo.truncate(0)
  lo.write(array_buf)
  size = lo.size
  lo.close

  puts size
end

#Read from LO
pdf_bytes = nil 
ActiveRecord::Base.transaction do
  lo = manager.open(oid.to_i)
  pdf_bytes = lo.read(lo.size)
  lo.close
end

reader = PDFS::IText::PDF::PdfReader.new(pdf_bytes)
puts reader.getNumberOfPages