SSLContext和SSLSocketFactory createSocket线程安全吗？

Question

public class SSLHandler() {
    public Socket upgradeToSSL(Socket plainSocket) {
        SSLSocket sslContext = SSLContext.getInstance("TLS");
        TrustManager[] trustManager = new TrustManager[]{
            new MyOwnTrustManager()
        };

        sslContext.init(null, trustManager, null);
        SSLSocketFactory sslsocketfactory = sslContext.getSocketFactory();

        sslSocket = (SSLSocket) sslsocketfactory.createSocket(
                    remoteSocket,
                    remoteSocket.getInetAddress().getHostAddress(),
                    remoteSocket.getPort(),
                    true);

        return sslSocket;
    }
}

SSLHandler类在多个线程中使用，如下所示：

Socket plainSocket = new Socket(host, port);
//Do some stuff in plain text...

//Lets use TLS now
SSLHandler sslHandler = new SSLHandler();
sslHandler.upgradeToSSL(Socket plainSocket);

plainSocket = upgradeToSSL(plainSocket);

因此，为每个新线程创建一个SSLHandler。为了避免这种情况，我考虑使用单例模式重构SSLHandler：

public class SingletonSSLHandler() {
    private SSLSocket sslContext;
    private SSLSocketFactory sslSocketFactory;

    //GetInstance() and etc.

    private SingletonSSLHandler() {
        sslContext = SSLContext.getInstance("TLS");
        TrustManager[] trustManager = new TrustManager[]{
            new MyOwnTrustManager()
        };

        sslContext.init(null, trustManager, null);
        sslSocketFactory = sslContext.getSocketFactory();
    }

    public static Socket upgradeToSSL(Socket plainSocket) {

        sslSocket = (SSLSocket) sslsocketfactory.createSocket(
                    remoteSocket,
                    remoteSocket.getInetAddress().getHostAddress(),
                    remoteSocket.getPort(),
                    true);

        return sslSocket;
    }
}

Answer 1

这个问题不是那么容易回答的。究其原因，有执行，更有合同层面。

实施

SSLServerSocketFactory类是抽象的，具有插件扩展机制。所以你不能确定从理论的角度来看你的实现是什么。

//
// The default factory does NOTHING.
//
class DefaultSSLServerSocketFactory extends SSLServerSocketFactory {
...
}