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我想上傳一個文件到我在Tomcat7上運行的Spring服務器。這是一個簡單的POST請求中，代碼如下：文件只部分上傳到服務器
@RequestMapping(method = RequestMethod.POST)
public void saveFile(HttpServletRequest request, @RequestParam("file_name") String fileName) {
Logger.getLogger(FileRestAction.class).info("saving file with name " + fileName);
try {
byte[] buf = readFromRequest(request);
String filePath = writeToFile(buf, fileName);
File_ file = new File_(filePath, request.getContentType());
Logger.getLogger(FileRestAction.class).info(request.getContentType() + " " + request.getContentLength());
fService.save(file);
} catch (IOException e) {
Logger.getLogger(FileRestAction.class).error("Failed to upload file. " +
"Exception is: " + e.getMessage());
}
}
private String writeToFile(byte[] buf, String fileName) throws IOException {
String fileBasePath = ConfigurationProvider.getConfig().getString(Const.FILE_SAVE_PATH);
File file = new File(fileBasePath + fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(buf);
fos.close();
Logger.getLogger(FileRestAction.class).info("filepath: " + file.getAbsolutePath());
return file.getAbsolutePath();
}
private byte[] readFromRequest(HttpServletRequest request) throws IOException {
InputStream is = request.getInputStream();
byte[] buf = new byte[request.getContentLength()];
is.read(buf);
is.close();
return buf;
}
現在的問題是，在服務器上的文件僅僅是「半完成」，就好像所有字節不存在。例如，如果我發送大小爲54kB的256x256 .png文件，則寫在服務器上的文件也是54kB和256x256大小，但實際圖片在開頭附近切斷（其餘爲空）。沒有例外被拋出。
位的測試之後，我發現，截止大約15-20Kb（以下圖片是完全上傳）。
關於什麼可能會導致此問題的任何想法？
編輯：我改變了readFromRequest方法根據什麼GreyBeardedGeek建議。現在如下：
private byte[] readFromRequest(HttpServletRequest request) throws IOException {
InputStream is = request.getInputStream();
int fileLength = (int) request.getContentLength();
byte[] buf = new byte[fileLength];
int bytesRead = 0;
while (true) {
bytesRead += is.read(buf, bytesRead, fileLength - bytesRead);
Logger.getLogger(FileRestAction.class).info("reading file: " + bytesRead + " bytes read");
if (bytesRead == fileLength) break;
}
is.close();
return buf;
}