我有一个要求,我需要在unix位置连续查找文件 . 一旦它可用,那么我需要解析它并转换为一些json格式 . 这需要使用Spring集成 - DSL完成 . 以下是我从Spring网站获得的一段代码,但它显示以下异常:
o.s.integration.handler.LoggingHandler: org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application.processFileChannel'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers
以下是代码:
@SpringBootApplication
public class FileReadingJavaApplication {
public static void main(String[] args) {
new SpringApplicationBuilder(FileReadingJavaApplication.class)
.web(false)
.run(args);
}
@Bean
public IntegrationFlow fileReadingFlow() {
return IntegrationFlows
.from(s -> s.file(new File("Y://"))
.patternFilter("*.txt"),
e -> e.poller(Pollers.fixedDelay(1000)))
.transform(Transformers.fileToString())
.channel("processFileChannel")
.get();
}
}
新代码:
@SpringBootApplication公共类SpringIntegration {
public static void main(String[] args) {
new SpringApplicationBuilder(SpringIntegration.class)
.web(false)
.run(args);
}
@Bean
public SessionFactory<LsEntry> sftpSessionFactory() {
DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(true);
factory.setHost("ip");
factory.setPort(port);
factory.setUser("username");
factory.setPassword("pwd");
factory.setAllowUnknownKeys(true);
return new CachingSessionFactory<LsEntry>(factory);
}
@Bean
public SftpInboundFileSynchronizer sftpInboundFileSynchronizer() {
SftpInboundFileSynchronizer fileSynchronizer = new SftpInboundFileSynchronizer(sftpSessionFactory());
fileSynchronizer.setDeleteRemoteFiles(false);
fileSynchronizer.setRemoteDirectory("remote dir");
fileSynchronizer.setFilter(new SftpSimplePatternFileListFilter("*.txt"));
return fileSynchronizer;
}
@Bean
@InboundChannelAdapter(channel = "sftpChannel", poller = @Poller(fixedDelay = "1000", maxMessagesPerPoll = "1"))
public MessageSource ftpMessageSource() {
SftpInboundFileSynchronizingMessageSource source =
new SftpInboundFileSynchronizingMessageSource(sftpInboundFileSynchronizer());
source.setLocalFilter(new AcceptOnceFileListFilter<File>());
source.setLocalDirectory(new File("Local directory"));
return source;
}
@Bean
@ServiceActivator(inputChannel = "fileInputChannel")
public MessageHandler handler() {
return new MessageHandler() {
@Override
public void handleMessage(Message<?> message) throws MessagingException {
System.out.println("File Name : "+message.getPayload());
}
};
}
@Bean public static StandardIntegrationFlow processFileFlow(){return IntegrationFlows .from(“fileInputChannel”) . split() . handle(“fileProcessor”,“process”) . get();
}
@Bean
@InboundChannelAdapter(value = "fileInputChannel", poller = @Poller(fixedDelay = "1000"))
public MessageSource<File> fileReadingMessageSource() {
AcceptOnceFileListFilter<File> filters =new AcceptOnceFileListFilter<>();
FileReadingMessageSource source = new FileReadingMessageSource();
source.setAutoCreateDirectory(true);
source.setDirectory(new File("Local directory"));
source.setFilter(filters);
return source;
}
@Bean
public FileProcessor fileProcessor() {
return new FileProcessor();
}
@Bean
@ServiceActivator(inputChannel = "fileInputChannel")
public AmqpOutboundEndpoint amqpOutbound(AmqpTemplate amqpTemplate) {
AmqpOutboundEndpoint outbound = new AmqpOutboundEndpoint(amqpTemplate);
outbound.setExpectReply(true);
outbound.setRoutingKey("foo"); // default exchange - route to queue 'foo'
return outbound;
}
@MessagingGateway(defaultRequestChannel = "amqpOutboundChannel")
public interface MyGateway {
String sendToRabbit(String data);
}
}
FileProcessor:
公共类FileProcessor {
public void process(Message<String> msg) {
String content = msg.getPayload();
JSONObject jsonObject ;
Map<String, String> dataMap = new HashMap<String, String>();
for(int i=0;i<=content.length();i++){
String userId = content.substring(i+5,i+16);
dataMap = new HashMap<String, String>();
dataMap.put("username", username.trim());
i+=290; //each record of size 290 in file
jsonObject = new JSONObject(dataMap);
System.out.println(jsonObject);
}
}
}
1 回答
您的代码是正确的,但有一个例外情况告诉您需要从直接通道“processFileChannel”读取消息的内容 .
请阅读Spring Integration Reference Manual中有关不同 Channels 类型的更多信息 .
EDIT
Spring Integration中的一等公民之一是
MessageChannel
抽象 . 有关更多信息,请参见EIP .像
.channel("processFileChannel")
这样的定义意味着声明DirectChannel . 这种通道意味着在发送上接受消息并直接在send
进程中执行处理 . 在原始Java语言中,它可能听起来像:从另一个服务中调用一个服务 . 如果另一个尚未自动装配,则抛出NPE
.因此,如果您使用
DirectChannel
作为输出,则应该在某处声明订阅者 . 我不知道你的逻辑是什么,但这就是它的工作原理,没有别的选择来修复Dispatcher has no subscribers for channel
.虽然你可以使用其他一些
MessageChannel
类型 . 但为了这个目的,你应该阅读更多的文档,例如马克费舍尔Spring Integration in Action .