Apache Camel -- Hazelcast 主题发布/订阅 -- 如何在订阅者中序列化字符串消息

Question

我试图按照http://camel.apache.org/hazelcast-component.html#HazelcastComponent-topic 的示例代码通过 Hazelcast 进行发布/订阅测试。

下面列出了发布者和订阅者路由定义

<route>
    <from uri="direct:inbound" />
    <setHeader headerName="CamelHazelcastOperationType">
        <simple>${type:org.apache.camel.component.hazelcast.HazelcastConstants.PUBLISH_OPERATION}</simple>
    </setHeader>
    <to uri="hazelcast:topic:foo" />
</route>    

<route>
    <from uri="hazelcast:topic:foo" />
    <log message="from hazelcast topic:= ${body}" />
    <bean ref="inboundProcessor" method="processHazelcastMsg" />
</route>

在测试期间，我通过 direct:inbound 端点向发布者路由发送了一个类似 "{\"result\": \"InboundProcessor.processRequest success\"}" 的字符串。订阅者路由能够接收来自主题的消息并传递给处理器 bean。但是，我未能正确取回字符串...

这是我实现 bean 方法的方式

public void processHazelcastMsg(Exchange inEx) throws Exception{

    Map<String, Object> headers = inEx.getIn().getHeaders();

    System.out.println("Exchange > In msg > Body = " + inEx.getIn().getBody());
    System.out.println("Exchange > In msg > Body class = " + ObjectHelper.className(inEx.getIn().getBody()));
    DataAwareMessage msg = inEx.getIn().getBody(DataAwareMessage.class);

    byte[] b = serializeObject(msg.getMessageObject());
    String msgStr = new String(b, Charset.forName("utf-8"));

    System.out.println("Received msg string = " + msgStr);
}

private static byte[] serializeObject(Object object) throws IOException
{
    try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
             ObjectOutput out = new ObjectOutputStream(bos)) {
            out.writeObject(object);
            return bos.toByteArray();
        } 
}   

这是日志输出：

[  hz._hzInstance_1_dev.event-5] route4                         INFO  from hazelcast topic:= com.hazelcast.topic.impl.DataAwareMessage[source=foo]
Exchange > In msg > Body = com.hazelcast.topic.impl.DataAwareMessage[source=foo]
Exchange > In msg > Body class = com.hazelcast.topic.impl.DataAwareMessage
Received msg string = ��

我确实尝试过使用不同的编码（如 UTF-8/UTF-16... 等）来转换字符串，但仍然失败。想知道是否应该有另一种方法来取回订阅者中的正确字符串

Answer 1

对于 hazelcast 主题生产者，消息正文的类型为 Message。可以通过调用Message.getMessageObject()获取原始对象 ：

public void processHazelcastMsg(Exchange inEx) throws Exception {
  String msgStr = inEx.getIn().getBody(Message.class).getMessageObject().toString();
}