Spring Batch configuration error in processor
I want to set up a Spring Batch job but I am getting the following error, how can I solve it?
Mistake: 
Reader:
import org.springframework.batch.item.ItemReader;
public class MoviesReader implements ItemReader<SearchResponseRO>, StepExecutionListener {
@Override
public SearchResponseRO read() throws Exception {
return new SearchResponseRO();
}
}
CPU:
import org.springframework.batch.item.ItemProcessor;
public class MoviesProcessor implements ItemProcessor<SearchResponseRO, Movie> {
@Override
public Movie process(SearchResponseRO searchResponseRO) throws Exception {
return new Movie();
}
}
What do I need to change to fix the problem?
Thank you.
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You need to specify the type for the operation chunk
. In your case, it will be <SearchResponseRO, Movie>
.
return stepBuilderFactory.get("downloadStep").<SearchResponseRO, Movie>chunk(10)
.reader(reader)
.processor(processor)
.....
Without a type, it defaults to <Object, Object>
:
stepBuilderFactory.get("test").chunk(10)
.reader(new ItemReader<Object>() {
@Override
public Object read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException {
return null;
}
})
.processor(new ItemProcessor<Object, Object>() {
@Override
public Object process(Object o) throws Exception {
return null;
}
})
.writer(new ItemWriter<Object>() {
@Override
public void write(List<?> list) throws Exception {
}
})
.build();
If you look at the definition of a method chunk
, it accepts int
but returns SimpleStepBuilder<I, O>
. Since there is no way to provide types for I
and O
, you must essentially cast them to the values you want. I believe the syntax .<Type>
is just a convenience for direct casting when chaining calls, so the following two things should be the same:
public void castGenericReturnType() {
System.out.println(this.<Integer>genericReturn(1));
System.out.println((Integer) genericReturn(1));
}
public <I> I genericReturn(Object objectToCast) {
return (I) objectToCast;
}
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