对安全性有要求的网站一般使用https来加密传输的请求和响应。https离不开证书，关于证书不在多说。Apache的HttpClient支持https，

下面是官方的样例程序，程序中使用了my.store这个文件，

这个文件不是网站的证书，而是一份包含自己密码的自己的证书库。这个文件是需要自己生成的，使用jdk中的keytool命令可以很方便的生成my.store文件。步骤如下（以支付宝为例）：

1. 浏览器（以chrome为例）访问https://www.alipay.com/，点击域名左侧的小锁，可以查看支付宝的证书信息
   
   
   

2. 将支付包的证书信息导出，证书格式有很多中，der、cer等。随便选择即可。

3. 命令行或者shell执行 keytool     -import -alias "my alipay cert" -file www.alipay.com.cert     -keystore my.store,

如果keytool命令不识别，去检查一下jdk的环境变量是否设置正确。”my alipay cert”是个别名，随便取。“www.alipay.com.cert”这个文件就是从浏览器中导出的支付宝的证书。

“my.store”是生成的自己 的证书库文件。回车执行，效果如下：

OK，现在可以执行下面的代码了：

    package com.yeetrack.httpclient;

    /**

    * Created with IntelliJ IDEA.

    * User: victor

    * Date: 13-10-11

    * Time: 下午3:09

    * To change this template use File | Settings | File Templates.

    */

    import java.io.File;

    import java.io.FileInputStream;

    import java.security.KeyStore;

    import javax.net.ssl.SSLContext;

    import org.apache.http.HttpEntity;

    import org.apache.http.client.methods.CloseableHttpResponse;

    import org.apache.http.client.methods.HttpGet;

    import org.apache.http.conn.ssl.SSLContexts;

    import org.apache.http.conn.ssl.SSLConnectionSocketFactory;

    import org.apache.http.impl.client.CloseableHttpClient;

    import org.apache.http.impl.client.HttpClients;

    import org.apache.http.util.EntityUtils;

 

    /**

    * 代码展示了如果使用ssl context创建安全socket连接

    */

    public class ClientCustomSSL {

        public final static void main(String[] args) throws Exception {

            KeyStore trustStore  = KeyStore.getInstance(KeyStore.getDefaultType());

            //加载证书文件

            FileInputStream instream = new FileInputStream(new File("/home/victor/my.store"));

            try {

                trustStore.load(instream, "mypassword".toCharArray());

            } finally {

                instream.close();

            }

            SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore).build();

            SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext,

                    SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);

            CloseableHttpClient httpclient = HttpClients.custom()

                    .setSSLSocketFactory(sslsf)

                    .build();

            try

            {

                //访问支付宝

                HttpGet httpget = new HttpGet("https://www.alipay.com/");

                System.out.println("executing request" + httpget.getRequestLine());

                CloseableHttpResponse response = httpclient.execute(httpget);

                try {

                    HttpEntity entity = response.getEntity();

                    System.out.println("----------------------------------------");

                    System.out.println(response.getStatusLine());

                    if (entity != null) {

                        System.out.println(EntityUtils.toString(entity));

                    }

                } finally {

                    response.close();

                }

            } finally {

                httpclient.close();

            }

        }

    }