我的项目仅包含简单的文件上传表单和重定向以查看它。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，它会从应用引擎中抛出IO Exception。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Google云端存储的文件大小？文件大小正确小于10 MB是可以的。任何代码片段都会受到高度赞赏。谢谢。
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： 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>
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
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
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);
}
}
的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>
答案 0 :(得分：7)
尝试更改第二个is.read：
readBytes = is.read(b, 0, readBytes);
为：
readBytes = is.read(b, 0, BUFFER_SIZE);
如果您在某个时刻阅读速度更快，那么数据可用，readBytes设置为0并且它永远保持此值，因为它基本上正在执行is.read(b, 0, 0)。
更好 - 你应该检查是否有要写的数据：
while (readBytes != -1) {
if(readBytes > 0)
storage.storeFile(b, readBytes);
readBytes = is.read(b, 0, BUFFER_SIZE);
}