如何使Apache Commons HttpClient 3.1忽略HTTPS证书无效？

关于如何使Apache Commons HttpClient 3.1忽略HTTPS证书无效，我们可以通过以下几个步骤来实现：

首先，需要导入Apache Commons HttpClient 3.1相关的依赖库，如下所示：

   <groupId>commons-httpclient</groupId>
   <artifactId>commons-httpclient</artifactId>
   <version>3.1</version>
</dependency>

接下来，我们需要创建一个自定义的SecureProtocolSocketFactory，用于忽略HTTPS证书验证。以下是一个简单的实现：

import org.apache.commons.httpclient.protocol.ProtocolSocketFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

public class TrustAllProtocolSocketFactory implements ProtocolSocketFactory {

    private SSLContext sslContext = null;

    public TrustAllProtocolSocketFactory() {
        try {
            this.sslContext = SSLContext.getInstance("SSL");
            this.sslContext.init(null, new TrustManager[]{new TrustAllTrustManager()}, null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public Socket createSocket(String host, int port, InetAddress localAddress, int localPort) throws IOException {
        return this.sslContext.getSocketFactory().createSocket(host, port, localAddress, localPort);
    }

    @Override
    public Socket createSocket(String host, int port, InetAddress localAddress, int localPort, HttpConnectionParams params) throws IOException {
        return this.sslContext.getSocketFactory().createSocket(host, port, localAddress, localPort);
    }

    @Override
    public Socket createSocket(String host, int port) throws IOException {
        return this.sslContext.getSocketFactory().createSocket(host, port);
    }

    private static class TrustAllTrustManager implements X509TrustManager {

        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return new X509Certificate[0];
        }
    }
}

然后，我们需要将自定义的TrustAllProtocolSocketFactory注册到Apache Commons HttpClient 3.1中，以便在使用HTTPS时忽略证书验证。以下是如何注册自定义的TrustAllProtocolSocketFactory的示例：

import org.apache.commons.httpclient.protocol.Protocol;
import org.apache.commons.httpclient.protocol.ProtocolSocketFactory;

public class HttpClientUtils {

    public static void registerTrustAllProtocolSocketFactory() {
        ProtocolSocketFactory protocolSocketFactory = new TrustAllProtocolSocketFactory();
        Protocol.registerProtocol("https", new Protocol("https", (ProtocolSocketFactory) protocolSocketFactory, 443));
    }
}

最后，在使用Apache Commons HttpClient 3.1之前，我们需要调用HttpClientUtils.registerTrustAllProtocolSocketFactory()方法来注册自定义的TrustAllProtocolSocketFactory。这样，Apache Commons HttpClient 3.1就会在使用HTTPS时忽略证书验证了。

请注意，这种方法会导致所有HTTPS连接都不进行证书验证，因此存在安全风险。在实际生产环境中，请务必谨慎使用。