new StringBody("that stuff", Charset.forName("US-ASCII")));
FormBodyPart p3 = new FormBodyPart(
"field3",
new StringBody("all kind of stuff"));
multipart.addBodyPart(p1);
multipart.addBodyPart(p2);
multipart.addBodyPart(p3);
ByteArrayOutputStream out = new ByteArrayOutputStream();
multipart.writeTo(out);