而不是设置默认的套接字工厂(这在我看来是一件坏事)- yhis只会影响当前连接，而不是你试图打开的每一个SSL连接:

URLConnection connection = url.openConnection();
    // JMD - this is a better way to do it that doesn't override the default SSL factory.
    if (connection instanceof HttpsURLConnection)
    {
        HttpsURLConnection conHttps = (HttpsURLConnection) connection;
        // Set up a Trust all manager
        TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager()
        {

            public java.security.cert.X509Certificate[] getAcceptedIssuers()
            {
                return null;
            }

            public void checkClientTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
            {
            }

            public void checkServerTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
            {
            }
        } };

        // Get a new SSL context
        SSLContext sc = SSLContext.getInstance("TLSv1.2");
        sc.init(null, trustAllCerts, new java.security.SecureRandom());
        // Set our connection to use this SSL context, with the "Trust all" manager in place.
        conHttps.setSSLSocketFactory(sc.getSocketFactory());
        // Also force it to trust all hosts
        HostnameVerifier allHostsValid = new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };
        // and set the hostname verifier.
        conHttps.setHostnameVerifier(allHostsValid);
    }
InputStream stream = connection.getInputStream();

受下面annser的启发，我找到了一种信任自签名CA并保持信任默认CA的方法。

    File file = new File(System.getProperty("java.home"), "lib/security/cacerts");
    KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
    keyStore.load(new FileInputStream(file), "changeit".toCharArray());


    InputStream resourceAsStream = getClass().getClassLoader().getResourceAsStream("testCer.cer");
    Certificate certificate = CertificateFactory.getInstance("X.509").generateCertificate(resourceAsStream);
    keyStore.setCertificateEntry("my-server-alias", certificate);

    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
    trustManagerFactory.init(keyStore);

    SSLContext sslContext = SSLContexts.createDefault();
    sslContext.init(null, trustManagerFactory.getTrustManagers(), null);


    // check domain
    // SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext);

    // not check domain
    SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext,
            new String[]{"TLSv1","TLSv1.1","TLSv1.2","SSLv3"},null, NoopHostnameVerifier.INSTANCE);

    CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(socketFactory).build();
    factory.setHttpClient(httpClient);
    RestTemplate restTemplate = new RestTemplate(factory);

而不是设置默认的套接字工厂(这在我看来是一件坏事)- yhis只会影响当前连接，而不是你试图打开的每一个SSL连接:

URLConnection connection = url.openConnection();
    // JMD - this is a better way to do it that doesn't override the default SSL factory.
    if (connection instanceof HttpsURLConnection)
    {
        HttpsURLConnection conHttps = (HttpsURLConnection) connection;
        // Set up a Trust all manager
        TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager()
        {

            public java.security.cert.X509Certificate[] getAcceptedIssuers()
            {
                return null;
            }

            public void checkClientTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
            {
            }

            public void checkServerTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
            {
            }
        } };

        // Get a new SSL context
        SSLContext sc = SSLContext.getInstance("TLSv1.2");
        sc.init(null, trustAllCerts, new java.security.SecureRandom());
        // Set our connection to use this SSL context, with the "Trust all" manager in place.
        conHttps.setSSLSocketFactory(sc.getSocketFactory());
        // Also force it to trust all hosts
        HostnameVerifier allHostsValid = new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };
        // and set the hostname verifier.
        conHttps.setHostnameVerifier(allHostsValid);
    }
InputStream stream = connection.getInputStream();

使用浏览器从目标页面下载自签名证书，并使用默认密码将其添加到默认存储区:

keytool -import -v -trustcacerts -file selfsigned.crt -alias myserver -keystore /etc/alternatives/jre/lib/security/cacerts -storepass changeit

使用$JAVA_HOME/jre/lib/security/cacerts文件，我这里的例子来自Oracle linux 7.7。

信任所有SSL证书:— 如果希望在测试服务器上进行测试，可以绕过SSL。 但是不要将此代码用于生产。

public static class NukeSSLCerts {
protected static final String TAG = "NukeSSLCerts";

public static void nuke() {
    try {
        TrustManager[] trustAllCerts = new TrustManager[] { 
            new X509TrustManager() {
                public X509Certificate[] getAcceptedIssuers() {
                    X509Certificate[] myTrustedAnchors = new X509Certificate[0];  
                    return myTrustedAnchors;
                }

                @Override
                public void checkClientTrusted(X509Certificate[] certs, String authType) {}

                @Override
                public void checkServerTrusted(X509Certificate[] certs, String authType) {}
            }
        };

        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCerts, new SecureRandom());
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
            @Override
            public boolean verify(String arg0, SSLSession arg1) {
                return true;
            }
        });
    } catch (Exception e) { 
    }
}

}

请在Activity或应用程序类的onCreate()函数中调用此函数。

NukeSSLCerts.nuke();

这可以用于Android的Volley。

Kotlin中的变体

    @SuppressLint("CustomX509TrustManager", "TrustAllX509TrustManager")
    fun ignoreSsl() {
        val trustAllCerts: Array<TrustManager> = arrayOf(
            object : X509TrustManager {
                override fun getAcceptedIssuers(): Array<X509Certificate>? = null
                override fun checkClientTrusted(certs: Array<X509Certificate?>?, authType: String?) {}
                override fun checkServerTrusted(certs: Array<X509Certificate?>?, authType: String?) {}
            })
        val sc = SSLContext.getInstance("SSL")
        sc.init(null, trustAllCerts, SecureRandom())
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.socketFactory)
    }