Question

我正在尝试将2mb文件读入内存，然后将该文件发送到Web服务器。但我的内存异常。

         FileConnection fileConn = (FileConnection)Connector.open("file:///" + pictureURI.getString(), Connector.READ);
     InputStream fis = fileConn.openInputStream();
     long overallSize = fileConn.fileSize();

     int chunkSize = 2048;
     int length = 0;
     while (length < overallSize)
     {

        byte[] data = new byte[chunkSize];
        int readAmount = fis.read(data, 0, chunkSize);
        byte[] newImageData = new byte[rawImage.length + chunkSize];
        System.arraycopy(rawImage, 0, newImageData, 0, length);
        System.arraycopy(data, 0, newImageData, length, readAmount);
        rawImage = newImageData;
        length += readAmount;

     }
       fis.close();
        fileConn.close();

正在上传500kb文件。可能是什么原因？请详细说明。

我也在循环中尝试了这个但没有用，System.gc（）;

[编辑] https://stackoverflow.com/users/45668/malcolm让我走上正轨。现在我来到这里

  this.progress = progress;

  HttpConnection conn = null;
  OutputStream os = null;
  InputStream s = null;
  StringBuffer responseString = new StringBuffer();

  try
  {
     System.out.println(System.getProperty("HTTPClient.dontChunkRequests"));
     conn = (HttpConnection)Connector.open(url);
     //conn.setRequestProperty("User-Agent", "Profile/MIDP-2.1 Configuration/CLDC-1.1");
     conn.setRequestMethod(HttpConnection.POST);

     // The messages
     conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=---------------------------4664151417711");
     conn.setRequestProperty("Content-Length", "355");

     os = conn.openOutputStream();

     System.out.println("file name at upload " + fileName);
     String message1 = "";
     message1 += "-----------------------------4664151417711\r\n";
     message1 += "Content-Disposition: form-data; name=\"file\"; filename=\"" + fileName + "\"\r\n";
     message1 += "Content-Type: image/gif\r\n";
     message1 += "\r\n";

     os.write(message1.getBytes());

     System.gc();

     // Send the image
     int index = 0;
     int size = 2048;
     double progdouble;
     do
     {
        progdouble = ((double)index) / ((double)rawImage.length) * 100;
        progress.setValue((int)progdouble);

        if((index+size) > rawImage.length)
        {
           size = rawImage.length - index;
        }
        os.write(rawImage, index, size);
        index += size;

        System.gc();
     } while(index < rawImage.length);

     String message2 = "\r\n-----------------------------4664151417711\r\n";
     message2 += "Content-Disposition: form-data; name=\"number\"\r\n\r\n";
     message2 += this.user_phone_number;         

     os.write(message2.getBytes());

     String message3 = "\r\n-----------------------------4664151417711\r\n";
     message3 += "Content-Disposition: form-data; name=\"uuid\"\r\n\r\n";
     message3 += this.user_uuid;         

     os.write(message3.getBytes());

     String message4 = "\r\n-----------------------------4664151417711--\r\n";  

     os.write(message4.getBytes());


     os.flush();
     os.close();

     // Read

     s = conn.openInputStream();
     int ch, i = 0, maxSize = 16384;
     while(((ch = s.read())!= -1 ) & (i++ < maxSize)) 
     {
        responseString.append((char) ch);
     }

     conn.close();
     System.out.println("response =>"+responseString.toString());



     return responseString.toString();
  }
  catch (IOException ioe)
  {
     return ioe.toString();
  }

现在它在这里失败了..

[EDIT2]

// algorithm that will read 1024 bytes at a time 
        byte b[] = new byte[chunkSize];
        for (int i = 0; i < overallSize; i += chunkSize) { 

            if ((i + chunkSize) < overallSize) {
                fis.read(b, 0, chunkSize);
            } else {
                int left = (int)overallSize - i;
                fis.read(b, 0, left);
            }

            // writing into the output stream - ( these lines will cause the "memory leak", without these, it will not happen)
            os.write(b);
            System.gc(); 

            progdouble = ((double)i) / ((double)overallSize) * 100;
            progress.setValue((int)progdouble); 
        }
        os.flush();

提前致谢。

Answer 1

您沿途分配了大量新阵列，这是完全没必要的。每个new byte[]行分配一个新数组。

你应该读入一个大数组，你应该在循环之前分配一次。您可以轻松地执行此操作，因为您知道文件的确切大小。代码看起来像这样：

FileConnection fileConn;
InputStream is;

try {
    fileConn = (FileConnection) Connector.open("file:///" + pictureURI.getString(), Connector.READ);
    is = fileConn.openInputStream();

    long overallSize = fileConn.fileSize();
    if (overallSize > Integer.MAX_VALUE) throw new IllegalArgumentException("File is too large);
    byte[] imageData = new byte[(int) overallSize];
    int chunkSize = 2048;
    int bytesReadTotal = 0;
    while (bytesRead < overallSize) {
        int bytesRead = is.read(imageData, bytesReadTotal, Math.min(imageData.length - bytesReadTotal, chunkSize));
        if (bytesRead == -1) break;
        bytesReadTotal += bytesRead;
    }
} finally {
    if (is != null) is.close();
    if (fileConn != null) fileConn.close();
}

Answer 2

您的手机（Nokia x2-01 specs）限制为整个应用的2Mb堆空间。根据这些限制设计您的应用。

一次在内存中使用2Mb bytearray

J2ME诺基亚s40内存不足异常

2 个答案: