如何使用 Java 在 Google Cloud Storage 中插入 pdf 文件答案

【问题标题】：How to insert a pdf file in Google Cloud Storage using Java如何使用 Java 在 Google Cloud Storage 中插入 pdf 文件
【发布时间】：2019-01-13 14:18:15
【问题描述】：

我一直在尝试使用我的应用程序在 Google Cloud Storage 上上传 pdf 文件，但我无法这样做。我在网上搜索并找到了以下给出的代码，但问题是此代码在上传 txt 时很有用文件但不是 pdf 文件。当我尝试上传 pdf 文件时，它会成功上传，但当我尝试打开它时，它不会打开。我正在使用以下代码：

protected void doPost(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
RequestDispatcher rd=req.getRequestDispatcher("career-registration-successfull.jsp");
RequestDispatcher rd1=req.getRequestDispatcher("career-registration-failed.jsp");
String name="";
String email="";
long whatsapp=0;
long number=0;
String query="";
int flag1=0;
int flag2=0;
isMultipart = ServletFileUpload.isMultipartContent(req);
resp.setContentType("text/html");
java.io.PrintWriter out = resp.getWriter( );
FileInputStream fileInputStream = new FileInputStream("C:\\Users\\Subhanshu Bigasia\\Desktop\\Amazon.pdf");
Storage storage = StorageOptions.getDefaultInstance().getService();
Bucket bucket=storage.get(("combucket1eduvitae7"));
ServletFileUpload sfu = new ServletFileUpload(new DiskFileItemFactory());
String targetFileStr="";
try {
    List<FileItem>  fileName = sfu.parseRequest(req);
     for(FileItem f:fileName)
        {
        try {
            f.write (new File("C:\\Users\\Subhanshu Bigasia\\Desktop\\Afcat.pdf"));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //targetFileStr = readFile("/Users/tkmajdt/Documents/workspace/File1POC1/" + f.getName(),Charset.defaultCharset());
        targetFileStr = new String(Files.readAllBytes(Paths.get("C:\\Users\\Subhanshu Bigasia\\Desktop\\Afcat.pdf")));
        }
}
catch(Exception e) {
    e.printStackTrace();
}
BlobId blobId = BlobId.of("combucket1eduvitae", "my_blob_name1");
//Blob blob = bucket.create("my_blob_name1", targetFileStr.getBytes(), "text/plain");
Blob blob=bucket.create("myblob",fileInputStream, "text");

谁能帮忙解决这个问题。
提前谢谢你

【问题讨论】：

标签： java eclipse file-upload google-cloud-platform google-cloud-storage

【解决方案1】：

我用下面的代码解决了这个问题：

String name="";
String email="";
long whatsapp=0;
long number=0;
String query="";
int flag1=0;
int flag2=0;
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
resp.setContentType("text/html");
java.io.PrintWriter out = resp.getWriter( );
    if( !isMultipart ) {
   out.println("<html>");
   out.println("<head>");
   out.println("<title>Servlet upload</title>");  
   out.println("</head>");
   out.println("<body>");
   out.println("<p>No file uploaded</p>"); 
   out.println("</body>");
   out.println("</html>");
   return;
}

DiskFileItemFactory factory = new DiskFileItemFactory();

// maximum size that will be stored in memory
factory.setSizeThreshold(maxMemSize);

// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);

// maximum file size to be uploaded.
upload.setSizeMax( maxFileSize );

try { 
   // Parse the request to get file items.
   List fileItems = upload.parseRequest(req);

   // Process the uploaded file items
   Iterator i = fileItems.iterator();

   out.println("<html>");
   out.println("<head>");
   out.println("<title>Servlet upload</title>");  
   out.println("</head>");
   out.println("<body>");

   while ( i.hasNext () ) {
      FileItem fi = (FileItem)i.next();
      if ( !fi.isFormField () ) {
         // Get the uploaded file parameters
        try { String fieldName = fi.getFieldName();
         String fileName = fi.getName();
         String contentType = fi.getContentType();
         boolean isInMemory = fi.isInMemory();
         long sizeInBytes = fi.getSize();
         Date date=new Date();             
         System.out.println(("Uploaded Filename: " + fileName + "<br>"));
         flag1=1;
         File f1=new File("C:\\Users\\Subhanshu Bigasia\\Desktop\\amazon2.pdf");
         FileInputStream fileInputStream = (FileInputStream) fi.getInputStream();
         Storage storage = StorageOptions.getDefaultInstance().getService();
         Bucket bucket=storage.get(("combucket1eduvitae7"));
         ServletFileUpload sfu = new ServletFileUpload(new DiskFileItemFactory());
         BlobId blobId = BlobId.of("combucket1eduvitae", "my_blob_name1");
         //Blob blob = bucket.create("my_blob_name1", targetFileStr.getBytes(), "application/pdf");
         Blob blob=bucket.create(fileName+" "+date.toString(),fileInputStream,"application/pdf");
         flag1=1;
        }
        catch(Exception e) {
            flag1=0;
            e.printStackTrace();
        }
      }

注意我用过
Blob blob=bucket.create(fileName+" "+date.toString(),fileInputStream,"application/pdf");而不是
Blob blob=bucket.create(fileName+" "+date.toString(),fileInputStream,"text/plain");

【讨论】：

【解决方案2】：

首先关注Cloud Storage Client Libraries for Java documentation，这将使您入门。

您可以尝试使用 Java (found here) 将文件上传到 Cloud Storage 存储桶的示例：

/**
   * Uploads data to an object in a bucket.
   *
   * @param name the name of the destination object.
   * @param contentType the MIME type of the data.
   * @param file the file to upload.
   * @param bucketName the name of the bucket to create the object in.
   */
  public static void uploadFile(
      String name, String contentType, File file, String bucketName)
      throws IOException, GeneralSecurityException {
    InputStreamContent contentStream = new InputStreamContent(
        contentType, new FileInputStream(file));
    // Setting the length improves upload performance
    contentStream.setLength(file.length());
    StorageObject objectMetadata = new StorageObject()
        // Set the destination object name
        .setName(name)
        // Set the access control list to publicly read-only
        .setAcl(Arrays.asList(
            new ObjectAccessControl().setEntity("allUsers").setRole("READER")));

    // Do the insert
    Storage client = StorageFactory.getService();
    Storage.Objects.Insert insertRequest = client.objects().insert(
        bucketName, objectMetadata, contentStream);

    insertRequest.execute();
  }

您可以在 GitHub 存储库 here 中找到易于遵循的入门教程。请同时查看 Stack Overflow 线程 Upload image to Google Cloud Storage (Java)。

【讨论】：

感谢@komarkovich 的回复，但我的问题已经解决了。