title: Reading a binary file from the file system as a BLOB to use in rhino with javascript
body: <p>I'm planing to use SheetJS with rhino. And sheetjs takes a binary object(BLOB if i'm correct) as it's input. So i need to read a file from the system using stranded java I/O methods and store it into a blob before passing it to sheetjs. eg :-  </p>
  
  <pre><code>var XLDataWorkBook = XLSX.read(blobInput, {type : "binary"});
  </code></pre>
  
  <p>So how can i create a BLOB(or appropriate type) from a binary file in java in order to pass it in.  </p>
  
  <p>i guess i cant pass streams because i guess XLSX needs a completely created object to process. </p>