Apache HttpClient - 自定义SSL上下文

使用安全套接字层 (SSL)，您可以建立客户端和服务器之间的安全连接。它有助于保护敏感信息，例如信用卡号码、用户名、密码、PIN 码等。

您可以使用HttpClient库创建自己的SSL上下文，使连接更安全。

按照以下步骤使用HttpClient库自定义SSLContext：

步骤1 - 创建SSLContextBuilder对象

SSLContextBuilder是SSLContext对象的构建器。使用SSLContexts类的custom()方法创建其对象。

//Creating SSLContextBuilder object
SSLContextBuilder SSLBuilder = SSLContexts.custom();

步骤2 - 加载密钥库

在路径Java_home_directory/jre/lib/security/中，您可以找到名为cacerts的文件。将其保存为您的密钥库文件（扩展名为.jks）。使用SSLContextBuilder类的loadTrustMaterial()方法加载密钥库文件及其密码（默认情况下为changeit）。

//Loading the Keystore file
File file = new File("mykeystore.jks");
SSLBuilder = SSLBuilder.loadTrustMaterial(file, "changeit".toCharArray());

步骤3 - 构建SSLContext对象

SSLContext对象表示安全套接字协议实现。使用build()方法构建SSLContext。

//Building the SSLContext
SSLContext sslContext = SSLBuilder.build();

步骤4 - 创建SSLConnectionSocketFactory对象

SSLConnectionSocketFactory是用于TSL和SSL连接的分层套接字工厂。使用此方法，您可以使用受信任证书列表验证Https服务器并验证给定的Https服务器。

您可以通过多种方式创建它。根据您创建SSLConnectionSocketFactory对象的方式，您可以允许所有主机，只允许自签名证书，只允许特定协议等等。

要仅允许特定协议，请通过将SSLContext对象、表示需要支持的协议的字符串数组、表示需要支持的密码套件的字符串数组和HostnameVerifier对象传递给其构造函数来创建SSLConnectionSocketFactory对象。

new SSLConnectionSocketFactory(sslcontext, new String[]{"TLSv1"}, null,    
   SSLConnectionSocketFactory.getDefaultHostnameVerifier());

要允许所有主机，请通过传递SSLContext对象和NoopHostnameVerifier对象来创建SSLConnectionSocketFactory对象。

//Creating SSLConnectionSocketFactory SSLConnectionSocketFactory object
SSLConnectionSocketFactory sslConSocFactory = new SSLConnectionSocketFactory(sslcontext, new NoopHostnameVerifier());

步骤5 - 创建HttpClientBuilder对象

使用HttpClients类的custom()方法创建一个HttpClientBuilder对象。

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

步骤6 - 设置SSLConnectionSocketFactory对象

使用setSSLSocketFactory()方法将SSLConnectionSocketFactory对象设置为HttpClientBuilder。

//Setting the SSLConnectionSocketFactory
clientbuilder = clientbuilder.setSSLSocketFactory(sslConSocFactory);

步骤7 - 构建CloseableHttpClient对象

通过调用build()方法构建CloseableHttpClient对象。

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

步骤8 - 创建HttpGet对象

HttpGet类表示HTTP GET请求，它使用URI检索给定服务器的信息。

通过将表示URI的字符串传递给HttpGet类来创建一个HTTP GET请求。

//Creating the HttpGet request
HttpGet httpget = new HttpGet("https://example.com/");

步骤9 - 执行请求

使用execute()方法执行请求。

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

示例

以下示例演示了SSLContext的自定义：

import java.io.File;
import javax.net.ssl.SSLContext;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;

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

      //Creating SSLContextBuilder object
      SSLContextBuilder SSLBuilder = SSLContexts.custom();
  
      //Loading the Keystore file
      File file = new File("mykeystore.jks");
      SSLBuilder = SSLBuilder.loadTrustMaterial(file,
         "changeit".toCharArray());

      //Building the SSLContext usiong the build() method
      SSLContext sslcontext = SSLBuilder.build();
 
      //Creating SSLConnectionSocketFactory object
      SSLConnectionSocketFactory sslConSocFactory = new SSLConnectionSocketFactory(sslcontext, new NoopHostnameVerifier());
 
      //Creating HttpClientBuilder
      HttpClientBuilder clientbuilder = HttpClients.custom();

      //Setting the SSLConnectionSocketFactory
      clientbuilder = clientbuilder.setSSLSocketFactory(sslConSocFactory);

      //Building the CloseableHttpClient
      CloseableHttpClient httpclient = clientbuilder.build();
      
      //Creating the HttpGet request
      HttpGet httpget = new HttpGet("https://example.com/");
 
      //Executing the request
      HttpResponse httpresponse = httpclient.execute(httpget);

      //printing the status line
      System.out.println(httpresponse.getStatusLine());

      //Retrieving the HttpEntity and displaying the no.of bytes read
      HttpEntity entity = httpresponse.getEntity();
      if (entity != null) {
         System.out.println(EntityUtils.toByteArray(entity).length);
      } 
   }
}

输出

执行上述程序后，将生成以下输出。

HTTP/1.1 200 OK
1270

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