教程] 《开源框架-Afinal》之FinalHttp 01一步一脚

1.FinalHttp是什么 ：FinalHttp 对 HttpClient再次封装，最简洁的就是增加了许多回调的方法，对Get 和 Post 请求进行了简化。另外一点就是FinalHttp加入线程池操作，默认的Http请求池连接为3。下面是为FinalHttp可配置的操作。

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FinalHttp finalHttp = new FinalHttp(); finalHttp.addHeader("Accept-Charset", "UTF-8");//配置http请求头 finalHttp.configCharset("UTF-8"); finalHttp.configCookieStore(null); finalHttp.configRequestExecutionRetryCount(3);//请求错误重试次数 finalHttp.configSSLSocketFactory(null); finalHttp.configTimeout(5000);//超时时间 finalHttp.configUserAgent("Mozilla/5.0");//配置客户端信息

 

2.FinalHttp 之 Get

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//------------------get 请求-----------------------  public void get( String url, AjaxCallBack<? extends Object> callBack) {      get( url, null, callBack);  }     public void get( String url, AjaxParams params, AjaxCallBack<? extends Object> callBack) {      sendRequest(httpClient, httpContext, new HttpGet(getUrlWithQueryString(url, params)), null, callBack);  }      public void get( String url, Header[] headers, AjaxParams params, AjaxCallBack<? extends Object> callBack) {      HttpUriRequest request = new HttpGet(getUrlWithQueryString(url, params));      if(headers != null) request.setHeaders(headers);      sendRequest(httpClient, httpContext, request, null, callBack);  }

 

三个方法的却别在于：第二个增加了参数。第三个增加了http header。，此处，AjaxParams 是一个 map集合。来看看 sendRequest方法。

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protected <T> void sendRequest(DefaultHttpClient client, HttpContext httpContext, HttpUriRequest uriRequest, String contentType, AjaxCallBack<T> ajaxCallBack) {        if(contentType != null) {            uriRequest.addHeader("Content-Type", contentType);        }           new HttpHandler<T>(client, httpContext, ajaxCallBack,charset)        .executeOnExecutor(executor, uriRequest);       }

 

这里面 直接调用了一个类HttpHandler的executeOnExecutor方法，传入了一个重要的参数executor。看看这个类：HttpHandler

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public class  HttpHandler  <T> extends  AsyncTask<Object, Object, Object> implements EntityCallBack{            private final AjaxCallBack<T> callback;                    private int executionCount = 0;            public HttpHandler(AbstractHttpClient client, HttpContext context, AjaxCallBack<T> callback,String charset) {                 this.client = client;                 this.context = context;                 this.callback = callback;                 this.charset = charset;         }

 

这个类继承了 AsyncTask，这个 AsyncTask是作者 自定义的，它相对于android 自带的 AsyncTask：修改了线程池属性，让并发线程按顺序执行。之前好像有人提到使用 afinal 加载图片是一个一个加载的，原因可能就在这里了。
这个类还实现了自定义的一个接口，里面的这个方法是我们回调的方法：

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public interface EntityCallBack {         public void callBack(long count,long current,boolean mustNoticeUI); }

 

这表明了HttpHandler 是一个异步加载类，我精简掉方法中暂时不用的代码，很显然，他的异步方法应该在 这个方法中执行doInBackground：

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@Override         protected Object doInBackground(Object... params) {                                  try {                         publishProgress(UPDATE_START); // 开始                         makeRequestWithRetries((HttpUriRequest)params[0]);//调用                                            } catch (IOException e) {                         publishProgress(UPDATE_FAILURE,e,0,e.getMessage()); // 结束                 }                    return null;         }

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private void makeRequestWithRetries(HttpUriRequest request) throws IOException {                                    boolean retry = true;                 IOException cause = null;                 HttpRequestRetryHandler retryHandler = client.getHttpRequestRetryHandler();                 while (retry) {                         try {                                 if (!isCancelled()) {                                         [color=Red]HttpResponse response = client.execute(request, context);[/color]//这里就开始执行了                                         if (!isCancelled()) {                                                 handleResponse(response);                                         }                                 }                                 return;                         } catch (UnknownHostException e) {                                 publishProgress(UPDATE_FAILURE,e,0,"unknownHostException：can't resolve host");                                 return;                         } catch (IOException e) {                                 cause = e;                                 retry = retryHandler.retryRequest(cause, ++executionCount,context);                         } catch (NullPointerException e) {                                 cause = new IOException("NPE in HttpClient" + e.getMessage());                                 retry = retryHandler.retryRequest(cause, ++executionCount,context);                         }catch (Exception e) {                                 cause = new IOException("Exception" + e.getMessage());                                 retry = retryHandler.retryRequest(cause, ++executionCount,context);                         }                 }                 if(cause!=null)                         throw cause;                 else                         throw new IOException("未知网络错误");         }

HttpResponse response = client.execute(request, context);这就开始执行了。
retry = retryHandler.retryRequest(cause, ++executionCount,context);这里出现异常执行一次，次数加一次。直到你设置的次数超过为止，retryHandler 就会直接返回false 中断 while(retry)

 

 

http://www.kwstu.com/ArticleView/419895180_2013925101126966