使用Compositewriter的FlatfileItemWriter示例

import org.springframework.batch.item.*;
import org.springframework.batch.item.file.FlatFileItemWriter;
import org.springframework.batch.item.file.builder.FlatFileItemWriterBuilder;
import org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor;
import org.springframework.batch.item.file.transform.DelimitedLineAggregator;
import org.springframework.core.io.FileSystemResource;

public class FlatFileItemWriterExample {

    public static void main(String[] args) {
        // 假设我们有一个简单的POJO类
        public static class Person {
            private String firstName;
            private String lastName;

            // getters and setters
        }

        // 创建FlatFileItemWriter实例
        FlatFileItemWriter<Person> writer = new FlatFileItemWriterBuilder<Person>()
                .name("personItemWriter")
                .resource(new FileSystemResource("persons.csv"))
                .delimited()
                .names(new String[]{"firstName", "lastName"})
                .build();

        // 创建另一个FlatFileItemWriter实例，用于写入不同的文件
        FlatFileItemWriter<Person> anotherWriter = new FlatFileItemWriterBuilder<Person>()
                .name("anotherPersonItemWriter")
                .resource(new FileSystemResource("anotherPersons.csv"))
                .delimited()
                .names(new String[]{"firstName", "lastName"})
                .build();

        // 创建CompositeItemWriter
        CompositeItemWriter<Person> compositeWriter = new CompositeItemWriter<>();
        compositeWriter.setDelegates(Arrays.asList(writer, anotherWriter));

        // 假设我们有一个Person的列表
        List<Person> persons = Arrays.asList(
                new Person("John", "Doe"),
                new Person("Jane", "Doe")
        );

        // 使用compositeWriter写入数据
        try {
            compositeWriter.write(persons);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}