Question

我想从服务总线中提取消息。消息只不过是XML。我想使用PEEK_LOCK选项来实现目标。

目前，队列中没有消息。我的代码每30秒执行一次计划。如果队列中有任何消息，它将提取消息，否则将打印不再消息。

ReceiveMessageOptions opts = ReceiveMessageOptions.DEFAULT;
opts.setReceiveMode(ReceiveMode.PEEK_LOCK);
service.getQueue(queueName).getValue().setMaxSizeInMegabytes((long) 1);
BrokeredMessage message;
message = service.receiveQueueMessage(queueName).getValue();
StreamSource source = null;
ResponseEntity<String> response = null;
LOG.debug("Message: " + message);
// LOG.debug("message.getMessageId(): " + message.getMessageId());
// try {
if (message != null) {
    source = new StreamSource(message.getBody());
    StringWriter outWriter = new StringWriter();
    StreamResult result = new StreamResult(outWriter);
    TransformerFactory tFactory = TransformerFactory.newInstance();
    Transformer transformer = tFactory.newTransformer();
    transformer.transform(source, result);
    StringBuffer sb = outWriter.getBuffer();
    String finalstring = sb.toString();
    DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
    InputSource src = new InputSource();
    src.setCharacterStream(new StringReader(finalstring));

    Document doc = builder.parse(src);
    String ecnNo = doc.getElementsByTagName(xmlECNNoTag).item(0).getTextContent();

    LOG.info(ecnNo + " Is pulled from queue "); 
    if (LOG.isDebugEnabled()) {
        LOG.info("XML Content: " + finalstring);
    }
}
service.deleteMessage(message);

如果我删除了peek_lock代码，我的代码就可以了。使用peek_lock我收到此错误：

javax.xml.transform.TransformerException中： org.xml.sax.SAXParseException; lineNumber：1; columnNumber：50;白色 publicId和systemId之间需要空格。在 com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform（TransformerImpl.java:749）〜[na：1.8.0_66] at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform（TransformerImpl.java:351）〜[na：1.8.0_66] at com.jci.subscriber.service.PLMSubscriberMSServiceImpl.azureMessageSubscriber（PLMSubscriberMSServiceImpl.java:160）〜[classes /：na] at com.jci.subscriber.PLMSubscriberMSApplication.getXML（PLMSubscriberMSApplication.java:118） [classes /：na] at sun.reflect.GeneratedMethodAccessor101.invoke（未知来源）〜[na：na] at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）〜[na：1.8.0_66] at java.lang.reflect.Method.invoke（Method.java:497）〜[na：1.8.0_66] at org.springframework.scheduling.support.ScheduledMethodRunnable.run（ScheduledMethodRunnable.java:65） [spring-context-4.2.6.RELEASE.jar：4.2.6.RELEASE] at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run（DelegatingErrorHandlingRunnable.java:54） [spring-context-4.2.6.RELEASE.jar：4.2.6.RELEASE] at java.util.concurrent.Executors $ RunnableAdapter.call（Executors.java:511） [na：1.8.0_66] at java.util.concurrent.FutureTask.runAndReset（FutureTask.java:308） [na：1.8.0_66] at java.util.concurrent.ScheduledThreadPoolExecutor中的$ ScheduledFutureTask.access $ 301（ScheduledThreadPoolExecutor.java:180） [na：1.8.0_66] at java.util.concurrent.ScheduledThreadPoolExecutor中的$ ScheduledFutureTask.run（ScheduledThreadPoolExecutor.java:294） [na：1.8.0_66] at java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1142） [na：1.8.0_66] at java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（ThreadPoolExecutor.java:617） [na：1.8.0_66] at java.lang.Thread.run（Thread.java:745）[na：1.8.0_66] 引起：org.xml.sax.SAXParseException：需要空格在publicId和systemId之间。在 com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse（AbstractSAXParser.java:1239）〜[na：1.8.0_66] at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity（TransformerImpl.java:641）〜[na：1.8.0_66] at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform（TransformerImpl.java:737）〜[na：1.8.0_66] ...省略了15个常用帧

Answer 1

根据我的经验，根据我的经验，我认为问题是由peek_lock模式通过DocumentBuilder验证来自服务总线的消息的远程DTD架构引起的。

下面有一些解决方法。

尝试使用方法[DocumentBuilderFactory.setValidating(boolean validating)] 1来停用验证消息，如下所示。

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(false);
DocumentBuilder builder = factory.newDocumentBuilder();

尝试通过方法DocumentBuilder.setEntityResolver(EntityResolver er)为EntityResolver设置自定义DocumentBuilder对象，请参阅SO帖子Make DocumentBuilder.parse ignore DTD references的anwser。

builder.setEntityResolver(new EntityResolver() { @Override public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException { if (systemId.contains("foo.dtd")) { return new InputSource(new StringReader("")); } else { return null; } } });

尝试使用dom4j之类的第三方库来解析消息。

希望它有所帮助。如有任何疑虑，请随时告诉我。

从服务总线中提取消息时出现异常

1 个答案: