Question

在我的应用中，我需要从服务器下载多个图像。我使用这段代码来获取一个字节数组：

HttpConnection connection = null;
InputStream inputStream = null;
byte[] data = null;

try 
{ 
//connection = (HttpConnection)Connector.open(url);
connection = (HttpConnection)Connector.open(url, Connector.READ_WRITE, true);

        int responseCode = connection.getResponseCode();            
        if(responseCode == HttpConnection.HTTP_OK)
        {
            inputStream = connection.openInputStream();
            data = IOUtilities.streamToBytes(inputStream);  
            inputStream.close();
        }           
        connection.close();

        return data;
    }
    catch(IOException e)
    {
        return null;
    }

url的后缀为“; deviceSide = false; ConnectionType = MDS - public”（不含空格），并且运行良好。

问题是，对于没有SIM卡的手机，我们无法通过MDS服务器连接到互联网。所以我们改为使用连接工厂，让BB选择他想要的任何东西：

    ConnectionFactory connFact = new ConnectionFactory();
    ConnectionDescriptor connDesc;
    connDesc = connFact.getConnection(url);

    if (connDesc != null)
    {
        final HttpConnection httpConn;
        httpConn = (HttpConnection)connDesc.getConnection();
        try
        {
            httpConn.setRequestMethod(HttpConnection.GET);
            final int iResponseCode = httpConn.getResponseCode();
            if(iResponseCode == HttpConnection.HTTP_OK)
            {
                InputStream inputStream = null;
                try{
                    inputStream = httpConn.openInputStream();
                    byte[] data = IOUtilities.streamToBytes(inputStream);   
                    return data;
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                    return null;
                }
                finally{
                    try
                    {
                        inputStream.close();
                    } catch (IOException e)
                    {
                        e.printStackTrace();
                        return null;
                    }
                }
            }
        } 
        catch (IOException e) 
        {
            System.err.println("Caught IOException: " + e.getMessage());
        }
    }
    return null;

连接有效，因为它选择了好的前缀（在我们的例子中是interface = wifi），但这会产生另一个问题。

有些图片没有很好地下载，其中一些（每次尝试都不一样）都已损坏，但只有当手机使用wifi连接才能获取这些图片时。

我该如何避免这个问题？我必须使用什么方法来获得连接？是否可以检查用户是否拥有使用MDS的SIM卡 - 公共？

以下是损坏图片的示例：

error image http://nsa30.casimages.com/img/2012/06/28/120628033716123822.png

Answer 1

试试这个：

public static String buildURL(String url) {
    String connParams = "";


        if (WLANInfo.getWLANState() == WLANInfo.WLAN_STATE_CONNECTED) {
            connParams = ";interface=wifi"; //Connected to a WiFi access point.
        } else {
            int coverageStatus = CoverageInfo.getCoverageStatus();
            //
            if ((coverageStatus & CoverageInfo.COVERAGE_BIS_B) == CoverageInfo.COVERAGE_BIS_B) {
                connParams = ";deviceside=false;ConnectionType=mds-public";
            } else if ((coverageStatus & CoverageInfo.COVERAGE_DIRECT) == CoverageInfo.COVERAGE_DIRECT) {
                // Have network coverage and a WAP 2.0 service book record
                ServiceRecord record = getWAP2ServiceRecord();
                //
                if (record != null) {
                    connParams = ";deviceside=true;ConnectionUID=" + record.getUid();

                } else {
                    connParams = ";deviceside=true";
                }
            } else if ((coverageStatus & CoverageInfo.COVERAGE_MDS) == CoverageInfo.COVERAGE_MDS) {
                // Have an MDS service book and network coverage
                connParams = ";deviceside=false";
            }
        }

       Log.d("connection param"+url+connParams);

    //
    return url+connParams;
}

private static ServiceRecord getWAP2ServiceRecord() {
    String cid;
    String uid;
    ServiceBook sb = ServiceBook.getSB();
    ServiceRecord[] records = sb.getRecords();
    //
    for (int i = records.length -1; i >= 0; i--) {
        cid = records[i].getCid().toLowerCase();
        uid = records[i].getUid().toLowerCase();
        //
        if (cid.indexOf("wptcp") != -1 
                && records[i].getUid().toLowerCase().indexOf("wap2") !=-1 
                && uid.indexOf("wifi") == -1 
                && uid.indexOf("mms") == -1) {
            return records[i];
        }
    }
    //
    return null;
}

Answer 2

您可以查看BIS_B（MDS公开）的覆盖范围是否足够，但如果您尝试支持无SIM用户，则无法帮助您。我想知道问题是否在Wi-Fi连接和IOUtilities.streamToBytes（）之间无法比较。请按照API documents中的建议尝试编码。

Answer 3

当你追加interface = wifi时会发生什么？您是否可以运行附加到kb以下文章的网络诊断工具并运行所有已删除SIM的测试

http://supportforums.blackberry.com/t5/Java-Development/What-Is-Network-API-alternative-for-legacy-OS/ta-p/614822

另请注意，通过BES / MDS下载大型文件时，MDS会施加限制。请确保您查看下面的kb文章 http://supportforums.blackberry.com/t5/Java-Development/Download-large-files-using-the-BlackBerry-Mobile-Data-System/ta-p/44585

BlackBerry - 使用HttpConnection在WiFi上下载的图像已损坏

3 个答案: