Java中的客戶端共享已下載的文件已損壞

Question

我嘗試使用輸入流在服務器端創建文件，我從客戶端獲取。

創建的文件大小與原始文件相同。 但是當試圖打開它時顯示文件已損壞。

嘗試共享文件的客戶端服務器上的fileSharing.jsp （發件人）

HttpURLConnection httpURLConnection = null;
OutputStream os = null;
InputStream is = null;
try {
    File fileObj = new File("D://test.pdf");
    out.print("File Length " + fileObj.length() + " Name " + fileObj.getName());
    URL url = new URL("http://localhost:2080/Receiver/fileupload?filename=test.pdf&filelength=" + fileObj.length());
    httpURLConnection = (HttpURLConnection) url.openConnection();
    httpURLConnection.setDoOutput(true);
    httpURLConnection.setRequestMethod("POST");
    httpURLConnection.setRequestProperty("Content-Type", "multipart/mixed");
    httpURLConnection.setRequestProperty("Connection", "Keep-Alive");
    httpURLConnection.setRequestProperty("Cache-Control", "no-cache");
    httpURLConnection.setRequestProperty("Content-Disposition", "form-data; name=\"Dummy File Description\"");
    httpURLConnection.setChunkedStreamingMode(8192);
    httpURLConnection.connect();

    is = new BufferedInputStream(new FileInputStream(fileObj));
    os = new BufferedOutputStream(httpURLConnection.getOutputStream());

    byte[] buff = new byte[8192];
    int len = 0;
    while ((len = is.read(buff, 0, buff.length)) > 0) {
        os.write(buff, 0, len);
        os.flush();
    }
} catch (Exception e) {
    e.printStackTrace();
} finally {
    is.close();
    os.close();
    httpURLConnection.disconnect();
}

嘗試下載文件的服務器端的FileUploadController servlet （Receiver）

InputStream is = null;
OutputStream os = null;
try {
    is = request.getInputStream();
    int total = 0;
    int bytes = 0;
    os = new BufferedOutputStream(new FileOutputStream(new File("D://files//dummy.pdf")));
    byte[] buff = new byte[8192];
    while (true) {
        if ((bytes = is.read(new byte[8192])) == -1) {
            System.out.println("File shared successfully");
            System.out.println("Total " + total);
            break;
        }
        total = total + bytes;
        System.out.println("Length " + bytes);
        os.write(buff, 0, bytes);
        //os.flush();
    }
} catch (Exception e) {
    e.printStackTrace();
} finally {
    is.close();
    os.close();
}

Answer 1

在FileUploadController的讀取循環中，您實例化一個新數組並讀入它，但是您沒有繼續使用它繼續使用它：

 byte[] buff = new byte[8192];
 while(true){
     if((bytes = is.read(new byte[8192])) == -1){

然而，你給文件寫了一個 buff （它將充滿0字節，所以你將擁有一個具有正確長度的文件，但是它的數量為0而不是實際數據）。

用。替換最后一行

     if((bytes = is.read(buff)) == -1){