HttpClient使用者身份驗證

使用HttpClient，您可以連線到需要使用者名和密碼的網站。本章介紹如何針對要求輸入使用者名和密碼的站點執行用戶端請求。

第1步 - 建立CredentialsProvider物件
CredentialsProvider介面維護一個集合以儲存使用者登入憑據。可以通過範例化BasicCredentialsProvider類(此介面的預設實現)來建立其物件。

CredentialsProvider credentialsPovider = new BasicCredentialsProvider();

第2步 - 設定憑據

可以使用setCredentials()方法將所需憑據設定為CredentialsProvider物件。

此方法接受以下給出的兩個物件 -

• AuthScope物件 - 驗證範圍，指定主機名，埠號和驗證方案名稱等詳細資訊。
• Credentials物件 - 指定憑據(使用者名，密碼)。

使用setCredentials()方法為主機和代理設定憑據，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 - 建立HttpClientBuilder物件

使用HttpClients類的custom()方法建立HttpClientBuilder。

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

第4步 - 設定credentialsPovider
可以使用setDefaultCredentialsProvider()方法將上面建立的credentialsPovider物件設定為HttpClientBuilder。

將上一步中建立的CredentialProvider物件設定為用戶端構建器，方法是將其傳遞給CredentialsProvider object()方法，如下所示。

clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider);

第5步 - 構建CloseableHttpClient

使用HttpClientBuilder類的build()方法構建CloseableHttpClient物件。

CloseableHttpClient httpclient = clientbuilder.build();

第6步 - 建立一個HttpGet物件並執行它
通過範例化HttpGet類來建立HttpRequest物件。使用execute()方法執行此請求。

//Creating a HttpGet object
HttpGet httpget = new HttpGet("https://www.tw511.com/ ");

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

範例
以下是一個範例程式，演示了針對需要使用者身份驗證的目標站點執行HTTP請求。

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.kaops.com/", 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.kaops.com/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());
      }
   }
}

執行上面範例程式碼，得到以下結果：

GET
HTTP/1.1 200 OK
200