HttpClient代理验证

在本章中，将学习如何使用用户名和密码创建经过身份验证的HttpRequest，并使用示例将其通过代理隧道传送到目标主机。

第1步 - 创建CredentialsProvider对象
CredentialsProvider接口维护一个集合以保存用户登录凭据。可以通过实例化BasicCredentialsProvider类(此接口的默认实现)来创建其对象。

CredentialsProvider credentialsPovider = new BasicCredentialsProvider();

第2步 - 设置凭据
可以使用setCredentials()方法将所需凭据设置为CredentialsProvider对象。这个方法接受两个对象 -

• AuthScope对象 - 验证范围，指定主机名，端口号和验证方案名称等详细信息。
• Credentials对象 - 指定凭据(用户名，密码)。使用setCredentials()方法为主机和代理设置凭据，如下所示。

credsProvider.setCredentials(new AuthScope("example.com", 80), new
   UsernamePasswordCredentials("user", "mypass"));
credsProvider.setCredentials(new AuthScope("localhost", 8000), new
   UsernamePasswordCredentials("abc", "passwd"));

第3步 - 创建一个HttpClientBuilder对象

使用HttpClients类的custom()方法创建一个HttpClientBuilder，如下所示 -

//Creating the HttpClientBuilder
HttpClientBuilder clientbuilder = HttpClients.custom();

第4步 - 设置CredentialsProvider

可以使用setDefaultCredentialsProvider()方法将CredentialsProvider对象设置为HttpClientBuilder对象。将先前创建的CredentialsProvider对象传递给此方法。

clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider);

第5步 - 构建CloseableHttpClient
使用build()方法构建CloseableHttpClient对象。

CloseableHttpClient httpclient = clientbuilder.build();

第6步 - 创建代理和目标主机
通过实例化HttpHost类来创建目标和代理主机。

//Creating the target and proxy hosts
HttpHost target = new HttpHost("example.com", 80, "http");
HttpHost proxy = new HttpHost("localhost", 8000, "http");

第7步 - 设置代理并构建RequestConfig对象
使用custom()方法创建RequestConfig.Builder对象。使用setProxy()方法将先前创建的proxyHost对象设置为RequestConfig.Builder。最后，使用build()方法构建RequestConfig对象。

RequestConfig.Builder reqconfigconbuilder= RequestConfig.custom();
reqconfigconbuilder = reqconfigconbuilder.setProxy(proxyHost);
RequestConfig config = reqconfigconbuilder.build();

第8步 - 创建一个HttpGet请求对象并为其设置配置对象。
通过实例化HttpGet类来创建HttpGet对象。使用setConfig()方法将上一步中创建的配置对象设置为此对象。

//Create the HttpGet request object
HttpGet httpGet = new HttpGet("/");

//Setting the config to the request
httpget.setConfig(config);

第9步 - 执行请求
通过将HttpHost对象(目标)和请求(HttpGet)作为参数传递给execute()方法来执行请求。

HttpResponse httpResponse = httpclient.execute(targetHost, httpget);

示例

以下示例演示了如何使用用户名和密码通过代理执行HTTP请求。

import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;

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

      //Creating the CredentialsProvider object
      CredentialsProvider credsProvider = new BasicCredentialsProvider();

      //Setting the credentials
      credsProvider.setCredentials(new AuthScope("example.com", 80), 
         new UsernamePasswordCredentials("user", "mypass"));
      credsProvider.setCredentials(new AuthScope("localhost", 8000), 
         new UsernamePasswordCredentials("abc", "passwd"));

      //Creating the HttpClientBuilder
      HttpClientBuilder clientbuilder = HttpClients.custom();

      //Setting the credentials
      clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider);

      //Building the CloseableHttpClient object
      CloseableHttpClient httpclient = clientbuilder.build();


      //Create the target and proxy hosts
      HttpHost targetHost = new HttpHost("example.com", 80, "http");
      HttpHost proxyHost = new HttpHost("localhost", 8000, "http");

      //Setting the proxy
      RequestConfig.Builder reqconfigconbuilder= RequestConfig.custom();
      reqconfigconbuilder = reqconfigconbuilder.setProxy(proxyHost);
      RequestConfig config = reqconfigconbuilder.build();

      //Create the HttpGet request object
      HttpGet httpget = new HttpGet("/");

      //Setting the config to the request
      httpget.setConfig(config);

      //Printing the status line
      HttpResponse response = httpclient.execute(targetHost, httpget);
      System.out.println(response.getStatusLine());

   }
}

执行上面示例代码，得到以下结果：

HTTP/1.1 200 OK