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Apache Commons IO

FileUtils.writeByteArrayToFile(new File("pathname"), myByteArray)

或者，如果你坚持为自己工作……

try (FileOutputStream fos = new FileOutputStream("pathname")) {
   fos.write(myByteArray);
   //fos.close(); There is no more need for this line since you had created the instance of "fos" inside the try. And this will automatically close the OutputStream
}

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);
}

没有任何库:

try (FileOutputStream stream = new FileOutputStream(path)) {
    stream.write(bytes);
}

谷歌番石榴:

Files.write(bytes, new File(path));

使用Apache Commons:

FileUtils.writeByteArrayToFile(new File(path), bytes);

所有这些策略都要求您在某个时刻捕获IOException。

从Java 7开始，您可以使用try-with-resources语句来避免资源泄漏，并使您的代码更易于阅读。这里有更多。

要把你的byteArray写入一个文件，你会做:

try (FileOutputStream fos = new FileOutputStream("fullPathToFile")) {
    fos.write(byteArray);
} catch (IOException ioe) {
    ioe.printStackTrace();
}

我知道它是用InputStream完成的

实际上，你会写入一个文件输出…