Напишите поток ввода в файл java
InputStream pdf = // greate some input stream data
try (FileOutputStream outputStream = new FileOutputStream(new File("/Users/kirkbrown/documents/my.pdf"))) {
int read;
byte[] bytes = new byte[1024];
while ((read = pdf.read(bytes)) != -1) {
outputStream.write(bytes, 0, read);
}
}
Kirk-Patrick Brown