你可以试试仙人掌:

new LengthOf(new TeeInput(array, new File("a.txt"))).value();

详情:http://www.yegor256.com/2017/06/22/object-oriented-input-output-in-cactoos.html

我知道它是用InputStream完成的

实际上，你会写入一个文件输出…

尝试OutputStream或者更具体地说FileOutputStream

基本的例子:

String fileName = "file.test";

BufferedOutputStream bs = null;

try {

    FileOutputStream fs = new FileOutputStream(new File(fileName));
    bs = new BufferedOutputStream(fs);
    bs.write(byte_array);
    bs.close();
    bs = null;

} catch (Exception e) {
    e.printStackTrace()
}

if (bs != null) try { bs.close(); } catch (Exception e) {}

File f = new File(fileName);    
byte[] fileContent = msg.getByteSequenceContent();    

Path path = Paths.get(f.getAbsolutePath());
try {
    Files.write(path, fileContent);
} catch (IOException ex) {
    Logger.getLogger(Agent2.class.getName()).log(Level.SEVERE, null, ex);
}

使用java.nio.file的另一个解决方案:

byte[] bytes = ...;
Path path = Paths.get("C:\\myfile.pdf");
Files.write(path, bytes);