本文共 3138 字，大约阅读时间需要 10 分钟。

HttpClient 4.2 中 简化了基于流畅风格的外观API。如果你不需要HttpClient丰富的灵活性，流畅风格API提供了HttpClient中最基础的方法，使用简单。比如：流畅风格API简化了使用者处理连接管理器和分配资源。

下面有几个例子：

// Execute a GET with timeout settings and return response content as String.Request.Get("http://somehost/")    .connectTimeout(1000)    .socketTimeout(1000)     .execute()    .returnContent().asString();

// Execute a POST with the 'expect-continue' handshake, using HTTP/1.1,// containing a request body as String and return response content as byte array.Request.Post("http://somehost/do-stuff")    .useExpectContinue()    .version(HttpVersion.HTTP_1_1)    .bodyString("Important stuff", ContentType.DEFAULT_TEXT)    .execute().returnContent().asBytes();

// Execute a POST with a custom header through the proxy containing a request body// as an HTML form and save the result to the fileRequest.Post("http://somehost/some-form")    .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"));

你也可以直接使用Executor，以一个特定的安全上下文执行请求，这样认证信息就会进行缓存并再用于后续请求。

Executor executor = Executor.newInstance()    .auth(new HttpHost("somehost"), "username", "password")    .auth(new HttpHost("myproxy", 8080), "username", "password")    .authPreemptive(new HttpHost("myproxy", 8080));executor.execute(Request.Get("http://somehost/"))    .returnContent().asString();executor.execute(Request.Post("http://somehost/do-stuff")    .useExpectContinue()    .bodyString("Important stuff", ContentType.DEFAULT_TEXT))    .returnContent().asString();

fluent facade API简化了使用者处理连接管理器和分配资源。在大多数情况下，它付出了在内存中缓存响应的代价。强烈建议使用ResponseHandler避免在内存中缓存响应。

Document result = Request.Get("http://somehost/content")  .execute()  .handleResponse(    new ResponseHandler
   
    () {      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);            }            String charset = contentType.getCharset();            if (charset == null) {                charset = HTTP.DEFAULT_CONTENT_CHARSET;            }            return docBuilder.parse(entity.getContent(), charset);        } catch (ParserConfigurationException ex) {            throw new IllegalStateException(ex);        } catch (SAXException ex) {            throw new ClientProtocolException("Malformed XML document", ex);        }    }  });
   

转载地址：http://zihgi.baihongyu.com/