《Apache HttpClient 4.3开发指南》
作者:chszs,转载需注明。博客主页:http://blog.csdn.net/chszs
一、概述
Apache HttpClient 4系列已经发布很久了,但由于它与HttpClient 3.x版本完全不兼容,以至于业内采用此库的公司较少,在互联网上也少有相关的文档资料分享。
本文旨在写一个简要的Apache HttpClient 4.3开发指南,帮助开发者快速上手Apache HttpClient 4.3.x库。
要注意的是,本文档中的代码在低于HttpClient 4.3版本的地方可能不能运行。
二、开发手册
1、创建HTTP客户端CloseableHttpClient client = HttpClientBuilder.create().build();
2、发送基本的GET请求
instance.execute(new HttpGet(“http://www.baidu.com”));
3、获取HTTP响应的状态码
String url = “http://www.baidu.com”; CloseableHttpResponse response = instance.execute(new HttpGet(url)); assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
4、获取响应的媒体类型
String url = “http://www.baidu.com”; CloseableHttpResponse response = instance.execute(new HttpGet(url)); String contentMimeType = ContentType.getOrDefault(response.getEntity()).getMimeType(); assertThat(contentMimeType, equalTo(ContentType.TEXT_HTML.getMimeType()));
5、获取响应的BODY部分
String url = “http://www.baidu.com”; CloseableHttpResponse response = instance.execute(new HttpGet(url)); String bodyAsString = EntityUtils.toString(response.getEntity()); assertThat(bodyAsString, notNullValue());
6、配置请求的超时设置
@Test(expected=SocketTimeoutException.class) public void givenLowTimeout_whenExecutingRequestWithTimeout_thenException() throws ClientProtocolException, IOException{ RequestConfig requestConfig = RequestConfig.custom() .setConnectionRequestTimeout(50).setConnectTimeout(50) .setSocketTimeout(50).build(); HttpGet request = new HttpGet(SAMPLE_URL); request.setConfig(requestConfig); instance.execute(request); }
7、发送POST请求
instance.execute(new HttpPost(SAMPLE_URL));
8、为HTTP请求配置重定向
CloseableHttpClient instance = HttpClientBuilder.create().disableRedirectHandling().build(); CloseableHttpResponse response = instance.execute(new HttpGet(SAMPLE_URL)); assertThat(reponse.getStatusLine().getStatusCode(), equalTo(301));
9、配置请求的HEADER部分
HttpGet request = new HttpGet(SAMPLE_URL); request.addHeader(HttpHeaders.ACCEPT, “application/xml”); response = instance.execute(request);
10、获取响应的HEADER部分
CloseableHttpResponse response = instance.execute(new HttpGet(SAMPLE_URL)); Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE); assertThat(headers, not(emptyArray()));
11、关闭或释放资源
response = instance.execute(new HttpGet(SAMPLE_URL)); try{ HttpEntity entity = response.getEntity(); if(entity!=null){ InputStream instream = entity.getContent(); instream.close(); } } finally{ response.close(); }
以上内容涵盖了HttpClient 4.3所有常见的需求,供开发者参考。