Apache HttpClient教程

Apache HttpClient - 用户身份验证

使用HttpClient，您可以连接到需要用户名和密码的网站.本章介绍如何针对要求输入用户名和密码的站点执行客户端请求.

步骤1 - 创建CredentialsProvider对象

CredentialsProvider Interface维护一个集合以保存用户登录凭据.您可以通过实例化 BasicCredentialsProvider 类来创建其对象，该类是此接口的默认实现.

CredentialsProvider credentialsPovider = new BasicCredentialsProvider();

步骤2 - 设置凭据

您可以使用将所需凭据设置为CredentialsProvider对象setCredentials()方法.

此方法接受下面给出的两个对象 :

AuthScope对象 : 身份验证范围指定主机名，端口号和身份验证方案名称等详细信息.
凭据对象 : 指定凭据(用户名，密码).

使用 setCredentials()方法为两者设置凭据主机和代理如下所示 :

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

步骤3 - 创建HttpClientBuilder对象

使用HttpClients 类的custom()方法创建HttpClientBuilder .

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

步骤4 - 设置credentialsPovider

您可以使用

将上一步创建的CredentialProvider对象设置为客户端构建器，方法是将其传递给 CredentialsProvider对象()方法如下所示.

clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider);

步骤5 - 构建CloseableHttpClient

使用 HttpClientBuilder 类的 build()方法构建 CloseableHttpClient 对象.

CloseableHttpClient httpclient = clientbuilder.build()

步骤6 - 创建HttpGet对象并执行它

通过实例化HttpGet类来创建HttpRequest对象.使用执行()方法执行此请求.

//Creating a HttpGet object
HttpGet httpget = new HttpGet("https://www.IT屋.com/ ");

//Executing the Get request
HttpResponse httpresponse = httpclient.execute(httpget);

示例

以下是一个示例程序，演示针对需要用户的目标站点执行HTTP请求身份验证.

import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
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 UserAuthenticationExample {
   
   public static void main(String args[]) throws Exception{
      
      //Create an object of credentialsProvider
      CredentialsProvider credentialsPovider = new BasicCredentialsProvider();

      //Set the credentials
      AuthScope scope = new AuthScope("https://www.IT屋.com/questions/", 80);
      
      Credentials credentials = new UsernamePasswordCredentials("USERNAME", "PASSWORD");
      credentialsPovider.setCredentials(scope,credentials);

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

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

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

      //Creating a HttpGet object
      HttpGet httpget = new HttpGet("https://www.IT屋.com/questions/index.php");

      //Printing the method used
      System.out.println(httpget.getMethod()); 

      //Executing the Get request
      HttpResponse httpresponse = httpclient.execute(httpget);

      //Printing the status line
      System.out.println(httpresponse.getStatusLine());
      int statusCode = httpresponse.getStatusLine().getStatusCode();
      System.out.println(statusCode);

      Header[] headers= httpresponse.getAllHeaders();
      for (int i = 0; i<headers.length;i++) {
         System.out.println(headers[i].getName());
      }
   } 
}