深入解析Spring Batch：企业级批处理框架的技术之旅

import org.springframework.batch.core.Job;
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.StepScope;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.batch.core.step.builder.StepBuilder;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.database.JdbcBatchItemWriter;
import org.springframework.batch.item.database.JdbcCursorItemReader;
import org.springframework.batch.item.database.builder.JdbcBatchItemWriterBuilder;
import org.springframework.batch.item.database.builder.JdbcCursorItemReaderBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import javax.sql.DataSource;

@Configuration
@EnableBatchProcessing
public class BatchConfiguration {

    // 定义数据源，这里使用内存数据库H2作为示例
    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("org.h2.Driver");
        dataSource.setUrl("jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1");
        dataSource.setUsername("sa");
        dataSource.setPassword("");
        return dataSource;
    }

    // 定义JdbcTemplate，用于执行SQL语句
    @Bean
    public JdbcTemplate jdbcTemplate(DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    // 定义ItemReader，从source_table表中读取数据
    @Bean
    public ItemReader<MyData> itemReader(DataSource dataSource) {
        return new JdbcCursorItemReaderBuilder<MyData>()
                .dataSource(dataSource)
                .sql("SELECT id, data FROM source_table")
                .rowMapper(new MyDataRowMapper())
                .build();
    }

    // 定义ItemProcessor，对读取的数据进行处理
    @Bean
    @StepScope
    public ItemProcessor<MyData, MyData> itemProcessor() {
        return new MyDataItemProcessor();
    }

    // 定义ItemWriter，将处理后的数据写入到target_table表中
    @Bean
    public ItemWriter<MyData> itemWriter(DataSource dataSource) {
        return new JdbcBatchItemWriterBuilder<MyData>()
                .dataSource(dataSource)
                .sql("INSERT INTO target_table (id, processed_data) VALUES (:id, :processedData)")
                .beanMapped()
                .build();
    }

    // 定义Step，将reader、processor和writer组合起来
    @Bean
    public Step step1(ItemReader<MyData> reader, ItemProcessor<MyData, MyData> processor, ItemWriter<MyData> writer) {
        return StepBuilder.create("step1")
                .<MyData, MyData>chunk(10)
                .reader(reader)
                .processor(processor)
                .writer(writer)
                .build();
    }

    // 定义Job，包含上面定义的Step
    @Bean
    public Job job(JobBuilderFactory jobBuilderFactory, @Qualifier("step1") Step step1) {
        return jobBuilderFactory.get("myJob")
                .incrementer(new RunIdIncrementer())
                .flow(step1)
                .end()
                .build();
    }

    // MyData类表示读取和处理的数据对象
    public static class MyData {
        private Long id;
        private String data;
        // getters and setters
    }

    // MyDataRowMapper类用于将数据库行映射为MyData对象
    public static class MyDataRowMapper implements org.springframework.jdbc.core.RowMapper<MyData> {
        @Override
        public MyData mapRow(org.springframework.jdbc.core.ResultSet rs, int rowNum) throws java.sql.SQLException {
            MyData myData = new MyData();
            myData.setId(rs.getLong("id"));
            myData.setData(rs.getString("data"));
            return myData;
        }
    }

    // MyDataItemProcessor类实现了ItemProcessor接口，对MyData对象进行处理
    public static class MyDataItemProcessor implements ItemProcessor<MyData, MyData> {
        @Override
        public MyData process(MyData item) throws Exception {
            // 对item进行处理，例如修改data字段的值
            item.setData(item.getData().toUpperCase());
            return item;
        }
    }
}