转自:
http://www.java265.com/JavaCourse/202205/3545.html
下文笔者讲述HTTPClient的示例分享,如下所示
HTTPClient: 是Apache旗下的产品,基于HttpCore HttpClient的官方参照文档:http://hc.apache.org/httpcomponents-client-ga/tutorial/pdf/httpclient-tutorial.pdf HttpClient使用步骤: 1.创建一个CloseableHttpClient实例 2.找一个可用的链接(uri) 3.执行httpclient.execute(uri) 4.response.close()
HttpClient的特性及优点
1. 基于java语言,实现了Http1.0和Http1.1 2. 以可扩展的面向对象的结构实现了Http全部的方法(GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE) 3. 支持HTTPS协议 4. 通过Http代理建立透明的连接 5. 利用CONNECT方法通过Http代理建立隧道的https连接 6. Basic, Digest, NTLMv1, NTLMv2, NTLM2 Session, SNPNEGO/Kerberos认证方案 7. 插件式的自定义认证方案。 8. 便携可靠的套接字工厂使它更容易的使用第三方解决方案 9. 连接管理器支持多线程应用。支持设置最大连接数,同时支持设置每个主机的最大连接数,发现并关闭过期的连接。 10. 自动处理Set-Cookie中的Cookie 11. 插件式的自定义Cookie策略 12. Request的输出流可以避免流中内容直接缓冲到socket服务器 13. Response的输入流可以有效的从socket服务器直接读取相应内容 14. 在http1.0和http1.1中利用KeepAlive保持持久连接 15. 直接获取服务器发送的response code和 headers 16. 设置连接超时的能力 17. 实验性的支持http1.1 response caching 18. 源代码基于Apache License 可免费获取
例
使用HttpClient访问指定url
CloseableHttpClient httpclient = HttpClients.createDefault(); HttpGet httpget = new HttpGet("http://localhost/"); CloseableHttpResponse response = httpclient.execute(httpget); try { <...> } finally { response.close(); }
例2:
spring中实例化CloseableHttpClient
@Autowired(required=false) private CloseableHttpClient httpClient; 然后在spring里建一个xml文件专门用于httpClient 关于URI的创建,官方提供了专门的api: HttpClient provides URIBuilder utility class to simplify creation and modification of request URIs URI uri = new URIBuilder() .setScheme("http") .setHost("www.google.com") .setPath("/search") .setParameter("q", "httpclient") .setParameter("btnG", "Google Search") .setParameter("aq", "f") .setParameter("oq", "") .build(); HttpGet httpget = new HttpGet(uri); HttpEntity entity = response.getEntity();
例3:
get请求的示例
public String doGet(String url,Map<String, String> params,String encode) throws Exception { if(null != params){ URIBuilder builder = new URIBuilder(url); for (Map.Entry<String, String> entry : params.entrySet()) { builder.setParameter(entry.getKey(), entry.getValue()); } url = builder.build().toString(); } HttpGet httpGet = new HttpGet(url); httpGet.setConfig(requestConfig); CloseableHttpResponse response = null; try { response = httpClient.execute(httpGet); if (response.getStatusLine().getStatusCode() == 200) { if(encode == null){ encode = "UTF-8"; } return EntityUtils.toString(response.getEntity(), encode); } } finally { if (response != null) { response.close(); } } return null; }
原文出处:HTTPClient示例分享