java-byte数组的保存姿势

public static void main(String[] args) throws IOException {
    File file = new File("");
    FileInputStream fileInputStream = new FileInputStream(file);
    // 用 ByteArrayOutputStream 将byte数组保存到内存中，并通过 toByteArray 方法一次性输出
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    byte[] b = new byte[1024];
    int read = 0;
    while ((read = fileInputStream.read(b)) > 0) {
        byteArrayOutputStream.write(b, 0, read);
    }
    System.out.println(Base64Util.encode(byteArrayOutputStream.toByteArray()));
}