HttpClient4.2 Fluent API学习
相比于HttpClient 之前的版本号,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仅仅暴露了一些最主要的HttpClient功能。
这样,Fluent API就将开发人员从连接管理、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)
还是利用详细样例来说明吧。
下面是几个使用Fluent API的代码例子:
一、最主要的http请求功能
运行Get、Post请求,不正确返回的响应作处理
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 { //运行一个GET请求,同一时候设置Timeout參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版本号协议运行一个POST请求,同一时候配置Expect-continue handshake达到性能调优, //请求中包括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(); //通过代理运行一个POST请求并加入一个自己定义的头部属性,请求包括一个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、在后台线程中异步运行多个请求
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>>(); // 异步运行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、更高速地启动请求
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); } }