HttpClient4.x客户端身份验证(HTTPS安全连接)

最近Apache HttpClient发布了最新的4.3版本，据说有很多的改进，加入了新的设计思想和理念，使API更加简洁有力，闲来无事，做个Demo尝尝鲜。

在以前的3.x版本中，HttpClient就已经支持HTTPS连接了，但是代码写的比较多，而且用起来感觉挺别扭的，同样的功能，到了4这里，明显得简单清爽多了。

如下是来自官方的一个例子，稍加改造，并翻译了注释：  

package cn.ysh.studio.crawler.httpclient;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.auth.AuthScope;import org.apache.http.auth.UsernamePasswordCredentials;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;/**
 * 演示如何使用HttpClient向需要身份验证的目标服务器发送HTTP请求
 * 
 * @author Shenghany
 * @date 2013-5-19
 */publicclassClientAuthentication{publicstaticvoid main(String[] args)throwsException{DefaultHttpClient httpclient =newDefaultHttpClient();try{//添加证书
            httpclient.getCredentialsProvider().setCredentials(newAuthScope("localhost",443),newUsernamePasswordCredentials("username","password"));//创建GET请求HttpGet httpget =newHttpGet("https://localhost/protected");System.out.println("executing request"+ httpget.getRequestLine());//执行请求HttpResponse response = httpclient.execute(httpget);//获得响应实体HttpEntity entity = response.getEntity();System.out.println("----------------------------------------");System.out.println(response.getStatusLine());if(entity !=null){System.out.println("Response content length: "+ entity.getContentLength());}//销毁实体EntityUtils.consume(entity);}finally{// 当不再需要HttpClient实例时,关闭连接管理器以确保释放所有占用的系统资源
            httpclient.getConnectionManager().shutdown();}}}