How can I get the number of line and the filename in itemProcessor - spring batch - spring

Question

I am using spring batch to parse my files. In ItemProcessor I validate if the incoming fields are correct. If they are not I want to throw a ValidationException and log to a file the corresponding row which has the incorrect fields. So, how can I find the number of line and the filename in ItemProcessor?

Answer 1

Without seeing you ItemReader config I can't really be sure but if you are using something like FlatFileItemReader to parse a csv, if in strict mode it will validate the number of columns.
Assuming you reader looks like this, that is:
<bean id="iItemReader" class="org.springframework.batch.item.file.FlatFileItemReader" scope="step">
<property name="linesToSkip" value="1"/>
<property name="comments" value="#" />
<property name="encoding" value="UTF-8"/>
<property name="lineMapper" >
<bean class="org.springframework.batch.item.file.mapping.DefaultLineMapper">
<property name="lineTokenizer">
<bean class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer">
<property name="delimiter" value=","/>
<property name="names">
<list >
<value>First_Field</value>
<value>Second_Field</value>
</list>
</property>
<property name="strict" value="true"/>
</bean>
</property>
<property name="fieldSetMapper">
<bean class="uk.co.package.FieldSetMapper">
<property name="dateFormat" value="yyyy-MM-dd HH:mm:ss"/>
</bean>
</property>
</bean>
</property>
</bean>
It will throw a FlatFileParseException for any lines that can't be processed. This includes the line number and can be handled in a listener.

Answer 2

As for the line number, you might build your own LineMapper and then store the line-number in your business object. An example in which I store the line unprocessed (as-is) together with the line number:
DefaultLineMapper<OneRow> lineMapper = new DefaultLineMapper<OneRow>() {
#Override
public OneRow mapLine(String line, int lineNumber) throws Exception {
return new OneRow(lineNumber, line);
}
};
Of course you can already map your Object, I had the need to have the whole line unprocessed as input to my Processors.
As a reference with the same idea: https://stackoverflow.com/a/23770421/5658642