JSON で大量のデータを生成する PHP ベースの Web サービスがあります。ここでは、説明のために 65KB のデータ サンプルを参照しています。65KB ならダウンロードにそれほど時間はかかりません。これを JavaScript (AJAX で呼び出す) でテストしたところ、データのパケットを取得するのに数ミリ秒かかりました。データが送受信されたタイムスタンプをマークするコードをサーバー側と Android クライアントに追加しました。 恐ろしいことに、ローカルホストでも Android シミュレーターが 65KB を取得するのに 2 分かかります。
これが私がデータを取得するために使用しているものです。1 つは HTTP 接続をキューに入れ、スレッドを使用して 1 つずつ実行し、もう 1 つは実際にデータを送受信し、ハンドラーのメソッドをトリガーするための 2 つのクラスです。
HTTPConnection.java:
public class HttpConnection implements Runnable
{
public static final int DID_START = 0;
public static final int DID_ERROR = 1;
public static final int DID_SUCCEED = 2;
private static final int GET = 0;
private static final int POST = 1;
private static final int PUT = 2;
private static final int DELETE = 3;
private static final int BITMAP = 4;
private String url;
private int method;
private Handler handler;
private List<NameValuePair> postData;
private String data;
private HttpClient httpClient;
public HttpConnection()
{
this(new Handler());
}
public HttpConnection(Handler _handler)
{
handler = _handler;
}
public void create(int method, String url, String data)
{
this.method = method;
this.url = url;
this.data = data;
ConnectionManager.getInstance().push(this);
}
public void createPost(int method, String url, List<NameValuePair>data)
{
this.method = method;
this.url = url;
this.postData = data;
ConnectionManager.getInstance().push(this);
}
public void get(String url)
{
create(GET, url, null);
}
public void post(String url, List<NameValuePair> data)
{
createPost(POST, url, data);
}
public void put(String url, String data)
{
create(PUT, url, data);
}
public void delete(String url)
{
create(DELETE, url, null);
}
public void bitmap(String url)
{
create(BITMAP, url, null);
}
public void run()
{
handler.sendMessage(Message.obtain(handler, HttpConnection.DID_START));
httpClient = new DefaultHttpClient();
HttpConnectionParams.setSoTimeout(httpClient.getParams(), 10000);
try {
HttpResponse response = null;
switch (method) {
case GET:
response = httpClient.execute(new HttpGet(url));
break;
case POST:
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(postData));
response = httpClient.execute(httpPost);
break;
case PUT:
HttpPut httpPut = new HttpPut(url);
httpPut.setEntity(new StringEntity(data));
response = httpClient.execute(httpPut);
break;
case DELETE:
response = httpClient.execute(new HttpDelete(url));
break;
case BITMAP:
response = httpClient.execute(new HttpGet(url));
processBitmapEntity(response.getEntity());
break;
}
if (method < BITMAP)
processEntity(response.getEntity());
} catch (Exception e) {
handler.sendMessage(Message.obtain(handler,
HttpConnection.DID_ERROR, e));
}
ConnectionManager.getInstance().didComplete(this);
}
private void processEntity(HttpEntity entity) throws IllegalStateException,IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(entity.getContent()));
String line, result = "";
while ((line = br.readLine()) != null)
result += line;
Message message = Message.obtain(handler, DID_SUCCEED, result);
handler.sendMessage(message);
}
private void processBitmapEntity(HttpEntity entity) throws IOException
{
BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity);
Bitmap bm = BitmapFactory.decodeStream(bufHttpEntity.getContent());
handler.sendMessage(Message.obtain(handler, DID_SUCCEED, bm));
}
}
ConnectionManager.java:
public class ConnectionManager
{
public static final int MAX_CONNECTIONS = 5;
private ArrayList<Runnable> active = new ArrayList<Runnable>();
private ArrayList<Runnable> queue = new ArrayList<Runnable>();
private static ConnectionManager instance;
public static ConnectionManager getInstance()
{
if (instance == null)
instance = new ConnectionManager();
return instance;
}
public void push(Runnable runnable)
{
queue.add(runnable);
if (active.size() < MAX_CONNECTIONS)
startNext();
}
private void startNext()
{
if (!queue.isEmpty())
{
Runnable next = queue.get(0);
queue.remove(0);
active.add(next);
Thread thread = new Thread(next);
thread.start();
}
}
public void didComplete(Runnable runnable)
{
active.remove(runnable);
startNext();
}
}
これらのコードは次のように呼ばれます。
public void SendHTTPRequest(String function, List<NameValuePair> Data, Handler handler)
{
new HttpConnection(handler).post(this.getServerAddress() + "/service-endpoint.php?function="+function,Data);
}