import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class FileByteUtil { public static void main(String[] args) throws Exception { File file=new File( "f:/test.doc "); byte[] fileByte = file2byte(file); byte2file(fileByte, "f:/test2.doc "); } public static byte[] file2byte(File f) throws Exception { return file2byte(f.getPath()); } public static byte[] file2byte(String f) throws Exception { try { InputStream in = new FileInputStream(f); byte[] tmp = new byte[512]; ByteArrayOutputStream out = new ByteArrayOutputStream(); int bytesRead = in.read(tmp); while (bytesRead != -1) { out.write(tmp, 0, bytesRead); bytesRead = in.read(tmp); } return out.toByteArray(); } catch (Exception e) { e.printStackTrace(); } return null; } // writes byte [] to a file public static void byte2file(byte[] data, String fn) throws Exception { try { OutputStream out = new FileOutputStream(fn); out.write(data); out.flush(); } catch (FileNotFoundException e) { throw e; } catch (IOException e) { throw e; } } }