流式传输 JSON 时 Android“意外结束流”

Question

所以我有一段代码，我正在调用服务器以获取一个大的 JSON 文件（大约 2MB）并使用 Jackson JSON Parser 解析它。代码运行良好，但问题是我有时会收到 IOException “意外结束流”。所以我猜我在流式传输过程中失去了我的模拟器上的连接。无论如何我可以暂停流并恢复它吗？或者重新连接然后恢复流？谢谢。

private void createDatabase(String downloadUrl)
{
    editor = sharedPref.edit();

    String fieldName = "";
    long id = 0;
    String setNumber = "";
    String cardName = "";
    String type = "";
    String attribute = "";
    String level = "";
    String category = "";
    String attack = "";
    String defense = "";
    String description = "";

    try
    {
        if (isOnline())
        {
            url = new URL(downloadUrl);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();

            jsonfactory = new JsonFactory();
            jsonParser = jsonfactory.createParser(connection.getInputStream());

            while (jsonParser.nextToken() != JsonToken.END_ARRAY)
            {
                if (jsonParser.getCurrentToken() == JsonToken.FIELD_NAME)
                {
                    fieldName = jsonParser.getCurrentName();

                    // if (fieldName.equals("id"))
                    // {
                    // jsonParser.nextToken();
                    // id = jsonParser.getIntValue();
                    // }

                    if (fieldName.equals("Set_Number"))
                    {
                        jsonParser.nextToken();
                        setNumber = jsonParser.getText();
                    }

                    else if (fieldName.equals("Card_Name"))
                    {
                        jsonParser.nextToken();
                        cardName = jsonParser.getText();
                    }

                    else if (fieldName.equals("Type"))
                    {
                        jsonParser.nextToken();
                        type = jsonParser.getText();
                    }

                    else if (fieldName.equals("Attribute"))
                    {
                        jsonParser.nextToken();
                        attribute = jsonParser.getText();
                    }

                    else if (fieldName.equals("Level"))
                    {
                        jsonParser.nextToken();
                        level = jsonParser.getText();
                    }

                    else if (fieldName.equals("Category"))
                    {
                        jsonParser.nextToken();
                        category = jsonParser.getText();
                    }

                    else if (fieldName.equals("Attack"))
                    {
                        jsonParser.nextToken();
                        attack = jsonParser.getText();
                    }

                    else if (fieldName.equals("Defense"))
                    {
                        jsonParser.nextToken();
                        defense = jsonParser.getText();
                    }

                    else if (fieldName.equals("Description"))
                    {
                        jsonParser.nextToken();
                        description = jsonParser.getText();
                    }
                }

                else if (jsonParser.getCurrentToken() == JsonToken.END_OBJECT)
                {
                    id = db.insert(setNumber, cardName, type, attribute, level, category, attack, defense, description);
                    editor.putLong("lastId", id);
                    editor.commit();
                }
            }
        }
    }

    catch (IOException e)
    {
        e.printStackTrace();
    }

    catch (Exception e)
    {
        e.printStackTrace();
    }

    finally
    {
        if (connection != null)
            connection.disconnect();

        if (jsonParser != null)
        {
            try
            {
                jsonParser.close();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }
    }

    Log.d("lastID", "" + sharedPref.getLong("lastId", -1));
    if (sharedPref.getLong("lastId", -1) == 5980)
    {
        editor.putBoolean("databaseExists", true);
        editor.commit();
    }
}

Answer 1

所以我想出了解决方案。看起来我连接到服务器的方式很糟糕。我找到了这段代码来获取 HTTP GET 响应并从中创建了一个 InputStream 并且它可以工作。祝其他尝试做同样事情的人好运。

        HttpClient httpclient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(downloadUrl);
        HttpResponse response = httpclient.execute(httpGet);
        HttpEntity entity = response.
        InputStream is = entity.getContent();

        jsonfactory = new JsonFactory();
        jsonParser = jsonfactory.createParser(is);

Answer 2

此处提到了有关暂停/恢复文件下载的详细信息。

Pause/Resume http connection download

注意： 如果您认为这是模拟器与互联网连接的问题，那么您也可以通过在设置下启用开发者选项来在手机上运行您的 apk。