Трябва да използвате ClassifierCompositeItemWriter
за да класифицирате елементи и да запишете всеки тип в съответния файл. Ето бърз пример, който можете да опитате:
import java.util.Arrays;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.file.FlatFileItemWriter;
import org.springframework.batch.item.file.builder.FlatFileItemWriterBuilder;
import org.springframework.batch.item.file.transform.PassThroughLineAggregator;
import org.springframework.batch.item.support.ClassifierCompositeItemWriter;
import org.springframework.batch.item.support.ListItemReader;
import org.springframework.classify.Classifier;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;
@Configuration
@EnableBatchProcessing
public class MyJob {
private JobBuilderFactory jobBuilderFactory;
private StepBuilderFactory stepBuilderFactory;
public MyJob(JobBuilderFactory jobBuilderFactory, StepBuilderFactory stepBuilderFactory) {
this.jobBuilderFactory = jobBuilderFactory;
this.stepBuilderFactory = stepBuilderFactory;
}
@Bean
public ItemReader<Person> itemReader() {
Person foo1 = new Person();foo1.setId(1);foo1.setName("foo1");
Person foo2 = new Person();foo2.setId(2);foo2.setName("foo2");
Person bar1 = new Person();bar1.setId(3);bar1.setName("bar1");
Person bar2 = new Person();bar2.setId(4);bar2.setName("bar2");
return new ListItemReader<>(Arrays.asList(foo1, foo2, bar1, bar2));
}
@Bean
public ClassifierCompositeItemWriter<Person> classifierCompositeItemWriter(ItemWriter<Person> fooItemWriter, ItemWriter<Person> barItemWriter) {
ClassifierCompositeItemWriter<Person> classifierCompositeItemWriter = new ClassifierCompositeItemWriter<>();
classifierCompositeItemWriter.setClassifier((Classifier<Person, ItemWriter<? super Person>>) person -> {
if (person.getName().startsWith("foo")) {
return fooItemWriter;
} else {
return barItemWriter;
}
});
return classifierCompositeItemWriter;
}
@Bean
public FlatFileItemWriter<Person> fooItemWriter() {
return new FlatFileItemWriterBuilder<Person>()
.name("fooItemWriter")
.resource(new FileSystemResource("foos.txt"))
.lineAggregator(new PassThroughLineAggregator<>())
.build();
}
@Bean
public FlatFileItemWriter<Person> barItemWriter() {
return new FlatFileItemWriterBuilder<Person>()
.name("barItemWriter")
.resource(new FileSystemResource("bars.txt"))
.lineAggregator(new PassThroughLineAggregator<>())
.build();
}
@Bean
public Step dataExtractionStep() {
return stepBuilderFactory.get("dataExtractionStep")
.<Person, Person>chunk(2)
.reader(itemReader())
.writer(classifierCompositeItemWriter(fooItemWriter(), barItemWriter()))
.stream(fooItemWriter())
.stream(barItemWriter())
.build();
}
@Bean
public Job dataExtractionJob() {
return jobBuilderFactory.get("dataExtractionJob")
.start(dataExtractionStep())
.build();
}
public static void main(String[] args) throws Exception {
ApplicationContext context = new AnnotationConfigApplicationContext(MyJob.class);
JobLauncher jobLauncher = context.getBean(JobLauncher.class);
Job job = context.getBean(Job.class);
jobLauncher.run(job, new JobParameters());
}
public static class Person {
private int id;
private String name;
public Person() {
}
public Person(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Person{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
}
Тази проба чете някои Person
елементи и записва тези с име foo*
към foos.txt
и тези с име bar*
към bars.txt
.
Надявам се това да помогне.