java 读取本地文件并转换为byte数组

　　　　　private byte[] InputStream2ByteArray(String filePath) throws IOException {

		InputStream in = new FileInputStream(filePath);
		byte[] data = toByteArray(in);
		in.close();

		return data;
	}

	private byte[] toByteArray(InputStream in) throws IOException {

		ByteArrayOutputStream out = new ByteArrayOutputStream();
		byte[] buffer = new byte[1024 * 4];
		int n = 0;
		while ((n = in.read(buffer)) != -1) {
			out.write(buffer, 0, n);
		}
		return out.toByteArray();
	}