未经Java认证即可访问HTTPS站点

Question

我想用我的Java代码访问一个https站点。首先，我使用了以下代码：

        URL url = new URL("https://an-example.com");
        HttpsURLConnection connection = (HttpsURLConnection)url.openConnection();
        connection.setRequestMethod("GET");
        connection.connect();

代码的最后一行面临异常：

javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No name matching an-example.com found
    at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
    at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1964)
    at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:328)
    at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:322)
    at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1614)
    at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
    at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1052)
    at sun.security.ssl.Handshaker.process_record(Handshaker.java:987)
    at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
    at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:162)
    at Main.fetchDataFromServer(Main.java:27)
    at Main.main(Main.java:16)
Caused by: java.security.cert.CertificateException: No name matching an-example.com found
    at sun.security.util.HostnameChecker.matchDNS(HostnameChecker.java:231)
    at sun.security.util.HostnameChecker.match(HostnameChecker.java:96)
    at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:455)
    at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:436)
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:200)
    at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
    at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1596)
    ... 12 more

然后我用了这个：

//         Create a trust manager that does not validate certificate chains
        TrustManager[] trustAllCerts = new TrustManager[] {new X509TrustManager() {
            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return null;
            }
            public void checkClientTrusted(X509Certificate[] certs, String authType) {
            }
            public void checkServerTrusted(X509Certificate[] certs, String authType) {
            }
        }
        };

        // Install the all-trusting trust manager
        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCerts, new java.security.SecureRandom());
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

        // Create all-trusting host name verifier
        HostnameVerifier allHostsValid = new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };

        // Install the all-trusting host verifier
        HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);

        URL url = new URL("https://an-example.com");

        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        Reader reader = new InputStreamReader(connection.getInputStream());

同样，最后一行代码面临异常：

Exception in thread "main" java.io.IOException: Server returned HTTP response code: 400 for URL: https://an-example.com
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1894)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263)
    at Example.main(Example.java:51)

我只想做一个简单的get-request。在浏览器中输入服务器地址时，会显示以下消息：

{
  "error": "invalid_request",
  "error_description": "Authorization header missing"
}

我只想在我的Java代码中得到此消息。我该怎么办？