snaker-core/src/main/java/org/snaker/engine/helper/StreamHelper.java
public static long copy(InputStream inputStream, OutputStream outputStream) throws IOException {
		return copy( inputStream, outputStream, DEFAULT_CHUNK_SIZE );
	}
public static long copy(InputStream inputStream, OutputStream outputStream) throws IOException {
		return copy( inputStream, outputStream, DEFAULT_CHUNK_SIZE );
	}
input->output字节流copy
@param inputStream
@param outputStream
@return
@throws IOException