在问一个问题：
能否有不通过异常方式处理的。getBean方法不传参数。

class Trans<T> {

        Object obj;

        public Trans(Object obj) {
            this.obj = obj;
        }

        public T getBean() {
            try {
                T t = (T) obj;
                return t;
            } catch (Exception e) {
                return null;
            }
        }
    }

最近在弄一些项目。大致意思见代码：

public class Test {

    public static void main(String[] args) {
        Test t = new Test();

        // begin
        MessageHolder messageHolder = t.new MessageHolder("从QUEUE中得到的其中一条");
        ServiceLoader<MessageReceiver> messageReceiverServiceLoader = ServiceLoader.load(MessageReceiver.class);
        Iterator<MessageReceiver> receiverIterator = messageReceiverServiceLoader.iterator();
        while (receiverIterator.hasNext()) {
            receiverIterator.next().doReceive(messageHolder);
        }
    }

    class MessageHolder<T> {

        Object obj;

        public MessageHolder(Object obj) {
            this.obj = obj;
        }

        public T getBean() {
            //将obj做各种处理或转化等，然后返回T
            try {
                T t = (T) obj;
                return t;
            } catch (Exception e) {
                return null;
            }
        }
    }

    abstract class MessageReceiver<T> {


        public void parse(MessageHolder<T> message) {
            T t = message.getBean();
            if (t != null) {
                doReceive(t);
            }
        }

        public abstract void doReceive(T messageVo);
    }

    /**
     * SPI配置中的一个实现类
     */
    class UserMsgReceiver extends MessageReceiver<Test> {

        public void doReceive(Test userInfo) {
            //do something with userInfo.
        }
    }
}