Apache Httpclient 简明教程
Apache HttpClient - User Authentication
使用 HttpClient，您可以连接到需要用户名和密码的网站。本章说明了如何针对询问用户名和密码的网站执行客户端请求。
Step 1 - Create a CredentialsProvider object
CredentialsProvider 接口维护一个用于保存用户登录凭据的集合。通过实例化 BasicCredentialsProvider 类（此接口的默认实现），您可以创建其对象。
CredentialsProvider credentialsPovider = new BasicCredentialsProvider();Step 2 - Set the Credentials
可以使用 setCredentials() 方法将所需凭据设置为 CredentialsProvider 对象。
此方法接受两个对象，如下所示 -
-
AuthScope object − 身份验证范围指定详细信息，如主机名、端口号和身份验证方案名称。
-
Credentials object - 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"));Step 3 - Create a HttpClientBuilder Object
使用 HttpClients 类的 custom() 方法创建一个 HttpClientBuilder 。
//Creating the HttpClientBuilder
HttpClientBuilder clientbuilder = HttpClients.custom();Step 4 - Set the credentialsPovider
可以使用 setDefaultCredentialsProvider() 方法将上面创建的 credentialsPovider 对象设置到 HttpClientBuilder。
通过将此前步骤中创建的 CredentialProvider 对象传递给 CredentialsProvider object() 方法，将其设置为客户端构建器，如下所示。
clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider);Step 5 - Build the CloseableHttpClient
使用 HttpClientBuilder 类的 build() 方法构建 CloseableHttpClient 对象。
CloseableHttpClient httpclient = clientbuilder.build()Step 6 - Create a HttpGet object and execute it
通过实例化 HttpGet 类创建一个 HttpRequest 对象。使用 execute() 方法执行此请求。
//Creating a HttpGet object
HttpGet httpget = new HttpGet("https://www.tutorialspoint.com/ ");
//Executing the Get request
HttpResponse httpresponse = httpclient.execute(httpget);Example
以下示例程序演示了针对需要用户身份验证的目标网站执行 HTTP 请求的过程。
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.tutorialspoint.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.tutorialspoint.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());
}
}
}