How to skip lines with ItemReader in Spring-Batch?

Question

I have a custom item reader that transforms lines from a textfile to my entity:

public class EntityItemReader extends AbstractItemStreamItemReader

        

Answer 1

For skipping lines you can throw Exception when you want to skip some lines, like below.

My Spring batch Step

@Bean
Step processStep() {

    return stepBuilderFactory.get("job step")
                .chunk(1000)
                .reader(ItemReader)
                .writer(DataWriter)
                .faultTolerant() //allowing spring batch to skip line 
                .skipLimit(1000) //skip line limit
                .skip(CustomException.class) //skip lines when this exception is thrown
                .build();
}

My Item reader

@Bean(name = "reader")
public FlatFileItemReader fileItemReader() throws Exception {

    FlatFileItemReader reader = new FlatFileItemReader();

    reader.setResource(resourceLoader.getResource("c://file_location/file.txt"));
    CustomLineMapper lineMapper = new CustomLineMapper();
    reader.setLineMapper(lineMapper);

    return reader;

    }

My custom line mapper

public class CustomLineMapper implements LineMapper {

@Override
public String mapLine(String s, int i) throws Exception {

    if(Condition) //put your condition here when you want to skip lines
        throw new CustomException();
    return s;
}
}