How to convert file to a string using SpringIntegration - spring

Question

I am trying to read a text file and convert it to a string using SpringIntegration.
Need help in transforming file to a string.
Git Link: https://github.com/ravikalla/spring-integration
Source Code -
#Bean
#InboundChannelAdapter(value = "payorFileSource", poller = #Poller(fixedDelay = "10000"))
public MessageSource<File> fileReadingMessageSource() {
FileReadingMessageSource sourceReader = new FileReadingMessageSource();
sourceReader.setDirectory(new File(INPUT_DIR));
sourceReader.setFilter(new SimplePatternFileListFilter(FILE_PATTERN));
return sourceReader;
}
#Bean
#Transformer(inputChannel="payorFileSource", outputChannel="payorFileContent")
public FileToStringTransformer transformFileToString() {
FileToStringTransformer objFileToStringTransformer = new FileToStringTransformer();
return objFileToStringTransformer;
}
Error -
SEVERE: org.springframework.integration.handler.ReplyRequiredException: No reply produced by handler 'fileCopyConfig.transformPayorStringToObject.transformer.handler', and its 'requiresReply' property is set to true., failedMessage=GenericMessage [payload=1|test1, headers={sequenceNumber=1, file_name=payor.txt, sequenceSize=4, correlationId=ff1fef7d-7011-ee99-8d71-96146ac9ea07, file_originalFile=source/payor.txt, id=fd4f950b-afcf-70e6-a053-7d59ff593add, file_relativePath=payor.txt, timestamp=1554875904858}]
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:119)

Answer 1

You can convert the file into an InputStream and the use
IOUtils.toString(inputStream) to convert it into a String.

Answer 2

That error is coming from somewhere else; the FTST can't return null.
I haven't looked at all your code, but this looks suspicious:
#Bean
#Transformer(inputChannel="payorRawStringChannel", outputChannel="payorRawObjectChannel")
public GenericTransformer<String, Payor> transformPayorStringToObject() {
return new GenericTransformer<String, Payor>() {
#Override
public Payor transform(String strPayor) {
String[] arrPayorData = strPayor.split(",");
Payor objPayor = null;
if (null != arrPayorData && arrPayorData.length > 1)
objPayor = new Payor(Integer.parseInt(arrPayorData[0]), arrPayorData[1]);
return objPayor;
}
};
}
It can return null; transformers are not allowed to do that.
Turn on DEBUG logging and follow the message flow to see which component is at fault.

Answer 3

package org.springframework.integration.samples.tcpclientserver;
import java.io.UnsupportedEncodingException;
import org.springframework.core.convert.converter.Converter;
/**
* Simple byte array to String converter; allowing the character set
* to be specified.
*
* #author Gary Russell
* #since 2.1
*
*/
public class ByteArrayToStringConverter implements Converter<byte[], String> {
private String charSet = "UTF-8";
public String convert(byte[] bytes) {
try {
return new String(bytes, this.charSet);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
return new String(bytes);
}
}
/**
* #return the charSet
*/
public String getCharSet() {
return charSet;
}
/**
* #param charSet the charSet to set
*/
public void setCharSet(String charSet) {
this.charSet = charSet;
}
}