通过HttpConnection下载大文件 [英] Downloading large file over HttpConnection

问题描述

使用以下代码我可以从url加载任何文件作为字节
，但这种方式适用于不大于256kb的文件。

Using the following code i can load any file from url as a bytes but this way works fine for file not larger than 256kb .

所以我想用另一种方法将较大的文件作为字节加载而不使用 BlackBerry Combiner

So I want another way to load larger files as bytes without using BlackBerry Combiner

我的代码：

HttpConnection hpc = null;
    try {
        hpc = (HttpConnection) Connector.open(url
                + ConnectionManager.getTimeOut(5000)
                + ConnectionManager.updateConnectionSuffix());
        hpc.setRequestMethod(HttpConnection.GET);
        hpc.setRequestProperty("Connection", "Keep-Alive");
        if (hpc.getResponseCode() != 200) {
            return null;
        }
        byte[] data = IOUtilities.streamToBytes(hpc.openInputStream());
        hpc.close();
        return data;
    } catch (Exception e) {
        return null;
    }

推荐答案

我试图调整 BlackBerry组合器
使用它下载大文件作为字节。它适用于我
下面列出的代码

i tried to adjust BlackBerry Combiner to use it on download large File as Bytes . and it works fine for me the code listed below

---调用

byte[] data = downloadLargeFiles(url);
                if (data != null) {
                    invoke(data.length + " ");
                    Bitmap bitmap = Bitmap.createBitmapFromBytes(data, 0,
                            data.length, 1);
                    manager.add(new BitmapField(bitmap));
                }

---函数

public byte[] downloadLargeFiles(String url) throws Exception {
    int chunkIndex = 0;
    int totalSize = 0;

    String currentFile = url + ConnectionManager.getTimeOut(5000)
            + ConnectionManager.updateConnectionSuffix();
    HttpConnection conn;
    InputStream in;
    int rangeStart = 0;
    int rangeEnd = 0;
    int chunksize = 100000;
    ByteArrayOutputStream bos = new ByteArrayOutputStream();

    while (true) {
        conn = (HttpConnection) Connector.open(currentFile,
                Connector.READ_WRITE, true);
        rangeStart = chunkIndex * chunksize;
        rangeEnd = rangeStart + chunksize - 1;
        conn.setRequestProperty("Range", "bytes=" + rangeStart + "-"
                + rangeEnd);
        int responseCode = conn.getResponseCode();
        if (responseCode != 200 && responseCode != 206) {
            // Dialog.alert("End "+responseCode);
            break;
        }
        in = conn.openInputStream();
        int length = -1;
        byte[] readBlock = new byte[256];
        int fileSize = 0;
        while ((length = in.read(readBlock)) != -1) {
            bos.write(readBlock, 0, length);
            fileSize += length;
            Thread.yield(); // Try not to get cut off
        }
        totalSize += fileSize;
        chunkIndex++; // index (range) increase
        in.close();
        conn.close();
        in = null;
        conn = null;

        Thread.sleep(1000);
    }
    bos.close();

    return bos.toByteArray();
}

谢谢

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