java - Apache httpclient 未知主机问题

Question

我正在使用以下 apache http 客户端片段，取自网站:

https://gist.github.com/Cyclenerd/41c737ee4b6ee4c767947af790d09e2c

这是发出简单获取请求的代码:

public final static void main(String[] args) throws Exception {
    // Setup a Trust Strategy that allows all certificates.
    // !!! DO NOT USE THIS IN PRODUCTION !!!
    SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(null, new TrustStrategy() {
        @Override
        public boolean isTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
            return true;
        }
    }).build();

    // Allow TLSv1 protocol only
    SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
            sslcontext,
            new String[] { "TLSv1" },
            null,
            SSLConnectionSocketFactory.getDefaultHostnameVerifier());
    CloseableHttpClient httpclient = HttpClients.custom()
            .setSSLSocketFactory(sslsf)
            .build();
    try {
        // Get URL
        HttpGet httpget = new HttpGet("https://www.google.de");

        System.out.println("Executing request " + httpget.getRequestLine());
        CloseableHttpResponse response = httpclient.execute(httpget);
        try {
            HttpEntity entity = response.getEntity();
            System.out.println("----------------------------------------");
            System.out.println(response.getStatusLine());
            System.out.println(EntityUtils.toString(entity));
        } finally {
            response.close();
        }
    } finally {
        httpclient.close();
    }
 }

我不断收到以下异常:

执行请求 GET https://www.google.de HTTP/1.1线程“main”中的异常 java.net.UnknownHostException:www.google.de

Answer 1

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;
import javax.net.ssl.SSLContext;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

public class StackOverFlowIssue {

    public final static void main(String[] args) throws Exception {
    // Setup a Trust Strategy that allows all certificates.
    // !!! DO NOT USE THIS IN PRODUCTION !!!
    SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(null, new TrustStrategy() {
        @Override
        public boolean isTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
            return true;
        }
    }).build();

    // Allow TLSv1 protocol only
    SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
            sslcontext,
            new String[] { "TLSv1" },
            null,
            SSLConnectionSocketFactory.getDefaultHostnameVerifier());
    CloseableHttpClient httpclient = HttpClients.custom()
            .setSSLSocketFactory(sslsf)
            .build();
    try {
        // Get URL
        HttpGet httpget = new HttpGet("https://www.google.de");

        System.out.println("Executing request " + httpget.getRequestLine());
        CloseableHttpResponse response = httpclient.execute(httpget);
        try {
            HttpEntity entity = response.getEntity();
            System.out.println("----------------------------------------");
            System.out.println(response.getStatusLine());
            System.out.println(EntityUtils.toString(entity));
        } finally {
            response.close();
        }
    } finally {
        httpclient.close();
    }
    }
}

Pom依赖

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpclient</artifactId>
  <version>4.5.3</version>
</dependency>