android-async-http解析和使用

loopj/android-async-http github地址
官网

Features

  • Make asynchronous HTTP requests, handle responses in anonymous callbacks
    发送异步http请求，在匿名callback对象中处理response信息；
  • HTTP requests happen outside the UI thread
    http请求发生在UI（主）线程之外的异步线程中；
  • Requests use a threadpool to cap concurrent resource usage
    内部采用线程池来处理并发请求；
  • GET/POST params builder (RequestParams)
    通过RequestParams类构造GET/POST，Builder方式。
  • Multipart file uploads with no additional third party libraries
    内置多部分文件上传，不需要第三方库支持；
  • Tiny size overhead to your application, only 60kb for everything
    和你的app大小相比来说，库的size很小，所有的一切只有90kb；
  • Automatic smart request retries optimized for spotty mobile connections
    在各种各样的移动连接环境中具备自动智能请求重试机制；
  • Automatic gzip response decoding support for super-fast requests
    自动的gzip响应解码
  • Optional built-in response parsing into JSON (JsonHttpResponseHandler)
    内置多种形式的响应解析，有原生的字节流，string，json对象，甚至可以将response写到文件中
  • Optional persistent cookie store, saves cookies into your app’s SharedPreferences
    cookie保存，内部实现用的是Android的SharedPreferences；

AsyncHttpClient 使用demo

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AsyncHttpClient client = new AsyncHttpClient();
   client.get("https://www.google.com", new AsyncHttpResponseHandler() {
       @Override
       public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
            System.out.println(response);
       }
       @Override
       public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable
   error)
   {
            error.printStackTrace(System.out);
       }
   });

整体操作流程

android-async-http最简单基础的使用只需如下步骤：

1、创建一个AsyncHttpClient；

2、（可选的）通过RequestParams对象设置请求参数；

3、调用AsyncHttpClient的某个get方法，传递你需要的（成功和失败时）callback接口实现，一般都是匿名内部类，实现了AsyncHttpResponseHandler，类库自己也提供许多现成的response handler，你一般不需要自己创建。

一、先创建一个AsyncHttpClient

AsyncHttpClient client = new AsyncHttpClient();

  • 1、创建SchemeRegistry，用于定义支持哪种协议（目前只支持http/https）

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    private static SchemeRegistry getDefaultSchemeRegistry(boolean fixNoHttpResponseException, int httpPort, int httpsPort) {
        //省略一系列参数判断。

        // Fix to SSL flaw in API < ICS
        // See https://code.google.com/p/android/issues/detail?id=13117
        SSLSocketFactory sslSocketFactory;
        if (fixNoHttpResponseException) {
            sslSocketFactory = MySSLSocketFactory.getFixedSocketFactory();
        } else {
            sslSocketFactory = SSLSocketFactory.getSocketFactory();
        }

        SchemeRegistry schemeRegistry = new SchemeRegistry();
        schemeRegistry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), httpPort));
        schemeRegistry.register(new Scheme("https", sslSocketFactory, httpsPort));

        return schemeRegistry;
    }

  • 2、初始化请求参数BasicHttpParams,添加Header

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    BasicHttpParams httpParams = new BasicHttpParams();

    ConnManagerParams.setTimeout(httpParams, connectTimeout);
    ConnManagerParams.setMaxConnectionsPerRoute(httpParams, new ConnPerRouteBean(maxConnections));
    ConnManagerParams.setMaxTotalConnections(httpParams, DEFAULT_MAX_CONNECTIONS);

    HttpConnectionParams.setSoTimeout(httpParams, responseTimeout);
    HttpConnectionParams.setConnectionTimeout(httpParams, connectTimeout);
    HttpConnectionParams.setTcpNoDelay(httpParams, true);
    HttpConnectionParams.setSocketBufferSize(httpParams, DEFAULT_SOCKET_BUFFER_SIZE);

    HttpProtocolParams.setVersion(httpParams, HttpVersion.HTTP_1_1);

  • 3、根据schemeRegistry 和 httpParams创建连接管理 ClientConnectionManager

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    ClientConnectionManager cm = createConnectionManager(schemeRegistry, httpParams);

  • 4、创建线程池

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    threadPool = getDefaultThreadPool();

  • 5、根据cm和httpParams创建HttpClient
    Creates a new HTTP client from parameters and a connection manager.

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    httpClient = new DefaultHttpClient(cm, httpParams);

  • 6、调用httpClient addRequestInterceptor和addResponseInterceptor，设置请求和反馈回调.

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    httpClient.addRequestInterceptor(new HttpRequestInterceptor() {
                @Override
                public void process(HttpRequest request, HttpContext context) {    //省略         
                }
            });

            httpClient.addResponseInterceptor(new HttpResponseInterceptor() {
                @Override
                public void process(HttpResponse response, HttpContext context) {
                   //省略 
                }
            });

            httpClient.addRequestInterceptor(new HttpRequestInterceptor() {
                @Override
                public void process(final HttpRequest request, final HttpContext context) throws HttpException, IOException {   
                 //省略             
                }
            }, 0);

  • 最后setHttpRequestRetryHandler,设置重试的Handler

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    httpClient.setHttpRequestRetryHandler(new RetryHandler(DEFAULT_MAX_RETRIES, DEFAULT_RETRY_SLEEP_TIME_MILLIS));

二、通过RequestParams对象设置请求参数；

传入key-value的键值对，作为请求参数

三、请求

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public RequestHandle get(String url, ResponseHandlerInterface responseHandler) {
    return get(null, url, null, responseHandler);
}

public RequestHandle get(Context context, String url, RequestParams params, ResponseHandlerInterface responseHandler) {
    return sendRequest(httpClient, httpContext, new HttpGet(getUrlWithQueryString(isUrlEncodingEnabled, url, params)), null, responseHandler, context);
}
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protected RequestHandle sendRequest(DefaultHttpClient client, HttpContext httpContext, HttpUriRequest uriRequest, String contentType, ResponseHandlerInterface responseHandler, Context context) {

        if (responseHandler.getUseSynchronousMode() && !responseHandler.getUsePoolThread()) {
            throw new IllegalArgumentException("Synchronous ResponseHandler used in AsyncHttpClient. You should create your response handler in a looper thread or use SyncHttpClient instead.");
        }

        if (contentType != null) {
            if (uriRequest instanceof HttpEntityEnclosingRequestBase && ((HttpEntityEnclosingRequestBase) uriRequest).getEntity() != null && uriRequest.containsHeader(HEADER_CONTENT_TYPE)) {
                log.w(LOG_TAG, "Passed contentType will be ignored because HttpEntity sets content type");
            } else {
                uriRequest.setHeader(HEADER_CONTENT_TYPE, contentType);
            }
        }

        responseHandler.setRequestHeaders(uriRequest.getAllHeaders());
        responseHandler.setRequestURI(uriRequest.getURI());

        //所有的请求处理都在这
        AsyncHttpRequest request = newAsyncHttpRequest(client, httpContext, uriRequest, contentType, responseHandler, context);
        //启用线程池
        threadPool.submit(request);
        //对AsyncHttpRequest进行了WeekReference包装。
        RequestHandle requestHandle = new RequestHandle(request);

        if (context != null) {
            List<RequestHandle> requestList;
            // Add request to request map
            synchronized (requestMap) {
                requestList = requestMap.get(context);
                if (requestList == null) {
                    requestList = Collections.synchronizedList(new LinkedList<RequestHandle>());
                    requestMap.put(context, requestList);
                }
            }

            requestList.add(requestHandle);

            Iterator<RequestHandle> iterator = requestList.iterator();
            while (iterator.hasNext()) {
                if (iterator.next().shouldBeGarbageCollected()) {
                    iterator.remove();
                }
            }
        }

        return requestHandle;
    }

最后官网推荐使用Static Http Client

Recommended Usage: Make a Static Http Client

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import com.loopj.android.http.*;

public class TwitterRestClient {
  private static final String BASE_URL = "https://api.twitter.com/1/";

  private static AsyncHttpClient client = new AsyncHttpClient();

  public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
      client.get(getAbsoluteUrl(url), params, responseHandler);
  }

  public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
      client.post(getAbsoluteUrl(url), params, responseHandler);
  }

  private static String getAbsoluteUrl(String relativeUrl) {
      return BASE_URL + relativeUrl;
  }
}

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import org.json.*;
import com.loopj.android.http.*;

class TwitterRestClientUsage {
    public void getPublicTimeline() throws JSONException {
        TwitterRestClient.get("statuses/public_timeline.json", null, new JsonHttpResponseHandler() {
            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                // If the response is JSONObject instead of expected JSONArray
            }
            
            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONArray timeline) {
                // Pull out the first event on the public timeline
                JSONObject firstEvent = timeline.get(0);
                String tweetText = firstEvent.getString("text");

                // Do something with the response
                System.out.println(tweetText);
            }
        });
    }
}

类图

#其他的用法见官网

  • Persistent Cookie Storage with PersistentCookieStore
  • Adding GET/POST Parameters with RequestParams
  • Uploading Files with RequestParams
  • Downloading Binary Data with FileAsyncHttpResponseHandler
  • Adding HTTP Basic Auth credentials