apache fluent api

    相比于HttpClient 之前的版本，HttpClient 4.2 提供了一组基于流接口(fluent interface)概念的更易使用的API，即Fluent API.

                为了方便使用，Fluent API只暴露了一些最基本的HttpClient功能。这样，Fluent API就将开发者从连接管理、资源释放等繁杂的操作中解放出来，从而更易进行一些HttpClient的简单操作。

(原文地址: http://blog.csdn.net/vector_yi/article/details/24298629 转载请注明出处)

                还是利用具体例子来说明吧。 

以下是几个使用Fluent API的代码样例：

一、最基本的http请求功能

执行Get、Post请求，不对返回的响应作处理 

package com.vectoryi.fluent;import java.io.File;import org.apache.http.HttpHost;import org.apache.http.HttpVersion;import org.apache.http.client.fluent.Form;import org.apache.http.client.fluent.Request;import org.apache.http.entity.ContentType;public class FluentRequests {    public static void main(String[] args)throws Exception {    //执行一个GET请求,同时设置Timeout参数并将响应内容作为String返回  Request.Get("http://blog.csdn.net/vector_yi")    .connectTimeout(1000)    .socketTimeout(1000)    .execute().returnContent().asString();  //以Http/1.1版本协议执行一个POST请求，同时配置Expect-continue handshake达到性能调优,  //请求中包含String类型的请求体并将响应内容作为byte[]返回  Request.Post("http://blog.csdn.net/vector_yi")    .useExpectContinue()    .version(HttpVersion.HTTP_1_1)    .bodyString("Important stuff", ContentType.DEFAULT_TEXT)    .execute().returnContent().asBytes();  //通过代理执行一个POST请求并添加一个自定义的头部属性,请求包含一个HTML表单类型的请求体  //将返回的响应内容存入文件  Request.Post("http://blog.csdn.net/vector_yi")    .addHeader("X-Custom-header", "stuff")    .viaProxy(new HttpHost("myproxy", 8080))    .bodyForm(Form.form().add("username", "vip").add("password", "secret").build())    .execute().saveContent(new File("result.dump"));    }}

二、在后台线程中异步执行多个请求

package com.vectoryi.fluent;import java.util.LinkedList;import java.util.Queue;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;import org.apache.http.client.fluent.Async;import org.apache.http.client.fluent.Content;import org.apache.http.client.fluent.Request;import org.apache.http.concurrent.FutureCallback;public class FluentAsync {  public static void main(String[] args)throws Exception {    // 利用线程池    ExecutorService threadpool = Executors.newFixedThreadPool(2);    Async async = Async.newInstance().use(threadpool);    Request[] requests = new Request[] {        Request.Get("http://www.google.com/"),        Request.Get("http://www.yahoo.com/"),        Request.Get("http://www.apache.com/"),        Request.Get("http://www.apple.com/")    };    Queue<Future<Content>> queue = new LinkedList<Future<Content>>();    // 异步执行GET请求    for (final Request request: requests) {      Future<Content> future = async.execute(request, new FutureCallback<Content>() {        public void failed(final Exception ex) {          System.out.println(ex.getMessage() + ": " + request);        }        public void completed(final Content content) {          System.out.println("Request completed: " + request);        }        public void cancelled() {        }      });      queue.add(future);    }    while(!queue.isEmpty()) {      Future<Content> future = queue.remove();      try {        future.get();      } catch (ExecutionException ex) {      }    }    System.out.println("Done");    threadpool.shutdown();  }}

三、更快速地启动请求

package com.vectoryi.fluent;import org.apache.http.client.fluent.Form;import org.apache.http.client.fluent.Request;public class FluentQuickStart {  public static void main(String[] args) throws Exception {    Request.Get("http://targethost/homepage")      .execute().returnContent();    Request.Post("http://targethost/login")      .bodyForm(Form.form().add("username",  "vip").add("password",  "secret").build())      .execute().returnContent();  }}

四、处理Response

在本例中是利用xmlparsers来解析返回的ContentType.APPLICATION_XML类型的内容。

package com.vectoryi.fluent;import java.io.IOException;import java.nio.charset.Charset;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import org.apache.http.Consts;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.StatusLine;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpResponseException;import org.apache.http.client.ResponseHandler;import org.apache.http.client.fluent.Request;import org.apache.http.entity.ContentType;import org.w3c.dom.Document;import org.xml.sax.SAXException;public class FluentResponseHandling {  public static void main(String[] args)throws Exception {    Document result = Request.Get("http://www.baidu.com")        .execute().handleResponse(new ResponseHandler<Document>() {      public Document handleResponse(final HttpResponse response) throws IOException {        StatusLine statusLine = response.getStatusLine();        HttpEntity entity = response.getEntity();        if (statusLine.getStatusCode() >= 300) {          throw new HttpResponseException(              statusLine.getStatusCode(),              statusLine.getReasonPhrase());        }        if (entity == null) {          throw new ClientProtocolException("Response contains no content");        }        DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance();        try {          DocumentBuilder docBuilder = dbfac.newDocumentBuilder();          ContentType contentType = ContentType.getOrDefault(entity);          if (!contentType.equals(ContentType.APPLICATION_XML)) {            throw new ClientProtocolException("Unexpected content type:" + contentType);          }          Charset charset = contentType.getCharset();          if (charset == null) {            charset = Consts.ISO_8859_1;          }          return docBuilder.parse(entity.getContent(), charset.name());        } catch (ParserConfigurationException ex) {          throw new IllegalStateException(ex);        } catch (SAXException ex) {          throw new ClientProtocolException("Malformed XML document", ex);        }      }      });    // 处理得到的result    System.out.println(result);  }}