我认为使用if-else或switch语句来选择实现是“可以的”。一个更好（更面向对象）的方法应该是这样的：

//////////////////////////////////
// The communication interfaces
//////////////////////////////////

public interface IChatCommunicationFactory {
    public String toString();
    public IChatCommunication create();
}

public interface IChatCommunication {
    public sendChatLine(String chatLine);
    public registerChatLineReceiver(IChatLineReceiver chatLineReceiver);
}

public interface IChatLineReceiver {
    public void onChatLineReceived(String chatLine);
}

//////////////////////////////////
// The communication interface implementations
//////////////////////////////////

public class XMLChatCommunicationFactory implements IChatCommunicationFactory {
    public String toString() {
        return "XML implementation";
    }

    public IChatCommunication create() {
        return new XMLChatCommunication();
    }
}

public class XMLChatCommunication implements IChatCommunication {
    private XMLProtocolSocket socket;

    public XMLChatCommunication() {
        // set up socket
    }

    public sendChatLine(String chatLine) {
        // send your chat line
    }

    public registerChatLineReceiver(IChatLineReceiver chatLineReceiver) {
        // start thread in which received chat lines are handled and then passed to the onChatLineReceived of the IChatLineReceiver
    }
}

// Do the same as above for the Serialization implementation.

//////////////////////////////////
// The user interface
//////////////////////////////////

public void fillListBoxWithCommuncationImplementations(ListBox listBox) {
    listBox.addItem(new XMLChatCommunicationFactory());
    listBox.addItem(new SerializationChatCommunicationFactory());
}

public IChatCommunication getChatCommunicationImplementationByUserSelection(ListBox listBox) {
    if (listBox.selectedItem == null)
        return null;

    IChatCommunicationFactory factory = (IChatCommunicationFactory)listBox.selectedItem;
    return factory.create();
}

您可以更进一步，实现类似 ChatCommunicationFactoryRegistry 每个 IChatCommunicationFactory 已注册。这将有助于将“业务”逻辑移出用户界面，因为 fillListBoxWithCommuncationImplementations() 方法只需要知道注册表，不再需要知道单个实现。

这里使用的“模式”是继承和简单的旧java。示例化要使用的实现，并在需要使用它的对象中保存对它的引用。当用户切换方法时，示例化新方法。