首先，我们需要导入HttpClient库，以便我们可以使用它来发送HTTP请求。以下是如何完成此操作的代码：
```java
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
```

然后，我们需要创建一个HttpGet对象，以便我们可以发送GET请求到指定的URL。以下是如何完成此操作的代码：
```java
HttpGet httpGet = new HttpGet("");
```

接下来，我们需要设置服务器的主机名和端口号。以下是如何完成此操作的代码：
```java
httpGet.setHeader("Proxy-Connection", "keep-alive");
httpGet.setHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)");
httpGet.setHeader("Host", "www.tmall.com");
httpGet.setHeader("Connection", "close");
httpGet.setHeader("Upgrade-Insecure-Requests", "1");
httpGet.setHeader("Cookie", "Hm_lvt_0c5f58739b795b1c08357f3525601a3c=1639181757,1639201337,1639203757,1639206157; Hm_lpvt_0c5f58739b795b1c08357f3525601a3c=1639206157");
httpGet.setHeader("Referer", "https://www.tmall.com/?spm=a1z12.3.0.0.838a66e07U86fA");
httpGet.setHeader("Accept-Encoding", "gzip, deflate");
httpGet.setHeader("Accept-Language", "zh-CN,zh;q=0.9");
httpGet.setHeader("Upgrade-Insecure-Requests", "1");
```

这就是如何使用HttpClient库来下载的完整代码。