教程] 《开源框架-Afinal》之FinalHttp 01一步一脚

转载

mb5fdcad0be2e90 2014-12-08 17:19:00

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。

1 2 3 4 5 6 7 8	`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

1 2 3 4 5 6 7 8 9 10 11 12 13 14	`//------------------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。

1 2 3 4 5 6 7 8 9	`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

1 2 3 4 5 6 7 8 9 10 11 12	`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：

1 2 3	`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：

1 2 3 4 5 6 7 8 9 10 11 12 13	`@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``;` `}`

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33	`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"``);` `}`