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为什么我无法通过应用引擎将大于 100KByte 的文件上传到 Google Cloud Storage?

Java问题
2022-01-01 2

Why I can#39;t upload file to Google Cloud Storage that larger than 100KByte through app engine?(为什么我无法通过应用引擎将大于 100KByte 的文件上传到 Google Cloud Storage?)

本文介绍了为什么我无法通过应用引擎将大于 100KByte 的文件上传到 Google Cloud Storage?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我的项目仅包含简单的文件上传表单和查看它的重定向.我可以上传任何小于 50 KB 的文件，但是当我上传一些大于 100 KB 的文件时，它会从应用引擎抛出 IO 异常.我不确定问题出在哪里.有谁知道如何通过应用引擎中的表单发布来增加我可以上传到谷歌云存储的文件大小?文件大小适当小于 10 MB 即可.任何代码片段将不胜感激.谢谢.

My project contains only simple file upload form and the redirect to view it. I can upload any files less than 50 KB but when I upload some files larger than 100 KB, it throws IO Exception from app engine. I am not sure where the problem is. Do anyone know how to increase the file size that I can upload to Google Cloud storage through the form posting in app engine? file size properly less than 10 MB is OK. Any code snippets would be vhighly appreciated. Thank you.

java.io.IOException
    at com.google.appengine.api.files.FileServiceImpl.translateException(FileServiceImpl.java:615)
    at com.google.appengine.api.files.FileServiceImpl.makeSyncCall(FileServiceImpl.java:588)
    at com.google.appengine.api.files.FileServiceImpl.append(FileServiceImpl.java:535)
    at com.google.appengine.api.files.FileServiceImpl.append(FileServiceImpl.java:289)
    at com.google.appengine.api.files.FileWriteChannelImpl.write(FileWriteChannelImpl.java:57)
    at com.google.appengine.api.files.FileWriteChannelImpl.write(FileWriteChannelImpl.java:46)
    at java.nio.channels.Channels.write(Channels.java:80)
    at java.nio.channels.Channels.access$000(Channels.java:64)
    at java.nio.channels.Channels$1.write(Channels.java:151)
    at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
    at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
    at storefile.StorageService.storeFile(StorageService.java:46)
    at storefile.UploadServlet.doPost(UploadServlet.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

以下是我的代码:上传.html

Following is my code: upload.html

<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Hello App Engine</title>
</head>

<body>
    <h1>Hello App Engine!</h1>
    <form action="/upload" method="post" enctype="multipart/form-data">
        <p>File<input type="file" name="file" /> </p>
        <p> <input type="submit"value="upload" /> <input type="reset" value="reset"/> </p>
    </form>
  </body>
</html>

上传Servlet.java

uploadServlet.java

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import com.google.appengine.api.blobstore.BlobKey;


public class UploadServlet extends HttpServlet{

   private static final long serialVersionUID = 1L;
  private StorageService storage = new StorageService();
  private static int BUFFER_SIZE =1024 * 1024* 10;
  @Override
   public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {

      resp.setContentType("text/plain");
      resp.getWriter().println("Now see here your file content, that you have uploaded on storage..");

      ServletFileUpload upload = new ServletFileUpload();
      FileItemIterator iter; 
   try {
    iter = upload.getItemIterator(req);
     while (iter.hasNext()) {
            FileItemStream item = iter.next();
            String fileName = item.getName();
            String mime = item.getContentType();

            storage.init(fileName, mime);
            InputStream is = new BufferedInputStream(item.openStream());

             byte[] b = new byte[BUFFER_SIZE];
            int readBytes = is.read(b, 0, BUFFER_SIZE);

            while (readBytes != -1) {
                storage.storeFile(b, readBytes);
                readBytes = is.read(b, 0, readBytes);
            }

             is.close();
            storage.destroy();

       resp.getWriter().println("File uploading done");

            // resp.getWriter().println("READ:" + storage.readTextFileOnly(fileName));
            BlobKey key = storage.getBlobkey(fileName);
            if (key != null) {
                resp.sendRedirect("/serve?blob-key=" + key.getKeyString());
            } else {
                resp.sendRedirect("/");
            }


      }
   } catch (Exception e) {
    e.printStackTrace(resp.getWriter());
    System.out.println("Exception::"+e.getMessage());
    e.printStackTrace();
   }
 }

}

StorageService.java

StorageService.java

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.nio.channels.Channels;
import java.util.logging.Logger;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;
import com.google.appengine.api.files.AppEngineFile;
import com.google.appengine.api.files.FileReadChannel;
import com.google.appengine.api.files.FileService;
import com.google.appengine.api.files.FileServiceFactory;
import com.google.appengine.api.files.FileWriteChannel;
import com.google.appengine.api.files.GSFileOptions.GSFileOptionsBuilder;

public class StorageService {

public static final String BUCKET_NAME = "aaaa";  

private FileWriteChannel writeChannel = null;
FileService fileService = FileServiceFactory.getFileService();

private BufferedOutputStream bos = null;
private static final Logger log = Logger.getLogger(StorageService.class.getName());
private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
public void init(String fileName, String mime) throws Exception {
 System.out.println("Storage service:init() method:  file name:"+fileName+" and mime:"+mime);
 log.info("Storage service:init() method:  file name:"+fileName+" and mime:"+mime);

    GSFileOptionsBuilder builder = new GSFileOptionsBuilder()
            .setAcl("public_read")
            .setBucket(BUCKET_NAME)
            .setKey(fileName)
            .setMimeType(mime);  
    AppEngineFile writableFile = fileService.createNewGSFile(builder.build());

    boolean lock = true;
    writeChannel = fileService.openWriteChannel(writableFile, lock);
    bos = new BufferedOutputStream(Channels.newOutputStream(writeChannel));
}

public void storeFile(byte[] b, int readSize) throws Exception { 
    bos.write(b,0,readSize);
    bos.flush();
}

    public void destroy() throws Exception {
     log.info("Storage service: destroy() method");
        bos.close();
        writeChannel.closeFinally();
    }
    public BlobKey getBlobkey (String filename) {
        BlobKey bk = blobstoreService.createGsBlobKey("/gs/aaaa/"+filename);
        return bk;
    }

}

fileserve.java

fileserve.java

import java.io.IOException;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;

public class fileserve extends HttpServlet {
    private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();

public void doGet(HttpServletRequest req, HttpServletResponse res)
    throws IOException {
        BlobKey blobKey = new BlobKey(req.getParameter("blob-key"));
        blobstoreService.serve(blobKey, res);
    }
}

web.xml

<?xml version="1.0" encoding="utf-8" standalone="no"?><web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>upload</servlet-name>
        <servlet-class>storefile.UploadServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>upload</servlet-name>
        <url-pattern>/upload</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>serve</servlet-name>
        <servlet-class>storefile.fileserve</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>serve</servlet-name>
        <url-pattern>/serve</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

推荐答案

尝试将第二个 is.read 从:

readBytes = is.read(b, 0, readBytes);

到:

readBytes = is.read(b, 0, BUFFER_SIZE);

如果在某些时候你的阅读速度更快，那么数据是可用的，readBytes 设置为 0 并且它永远保持在这个值，因为它基本上是在做 is.read(b, 0, 0).

If at some point you are reading faster then data is available, readBytes is set to 0 and it stays forever at this value, because it's basically doing is.read(b, 0, 0).

更好 - 你应该检查是否有数据要写入:

Even better - you should check if there is data to be written:

while (readBytes != -1) {
    if(readBytes > 0)
        storage.storeFile(b, readBytes);
    readBytes = is.read(b, 0, BUFFER_SIZE);
}

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