给我一个spring batch双数据源的例子，系统表写到H2，业务表写到DB2

好的，下面是一个简单的Spring Batch双数据源的例子，其中系统表写到H2，业务表写到DB2：

首先，需要在Spring Boot应用程序中配置两个数据源的连接信息。可以在application.yml（或application.properties）文件中添加以下配置：

spring:
  datasource:
    system:
      url: jdbc:h2:mem:testdb
      driver-class-name: org.h2.Driver
      username: sa
      password: password
    business:
      url: jdbc:db2://localhost:50000/mydb
      driver-class-name: com.ibm.db2.jcc.DB2Driver
      username: user
      password: password

然后，定义两个数据源的bean：

@Configuration
public class DataSourceConfig {
 
    @Bean(name = "systemDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.system")
    public DataSource systemDataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Bean(name = "businessDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.business")
    public DataSource businessDataSource() {
        return DataSourceBuilder.create().build();
    }
 
}

接下来，需要配置两个事务管理器和两个JdbcTemplate来访问两个数据源：

@Configuration
@EnableBatchProcessing
public class BatchConfig {
 
    @Autowired
    @Qualifier("systemDataSource")
    private DataSource systemDataSource;
 
    @Autowired
    @Qualifier("businessDataSource")
    private DataSource businessDataSource;
 
    @Bean(name = "systemTransactionManager")
    public PlatformTransactionManager systemTransactionManager() {
        return new DataSourceTransactionManager(systemDataSource);
    }
 
    @Bean(name = "businessTransactionManager")
    public PlatformTransactionManager businessTransactionManager() {
        return new DataSourceTransactionManager(businessDataSource);
    }
 
    @Bean(name = "systemJdbcTemplate")
    public JdbcTemplate systemJdbcTemplate() {
        return new JdbcTemplate(systemDataSource);
    }
 
    @Bean(name = "businessJdbcTemplate")
    public JdbcTemplate businessJdbcTemplate() {
        return new JdbcTemplate(businessDataSource);
    }
 
}

最后，在Job中使用两个JdbcTemplate访问两个数据源：

@Configuration
public class MyJobConfig {
 
    @Autowired
    @Qualifier("systemJdbcTemplate")
    private JdbcTemplate systemJdbcTemplate;
 
    @Autowired
    @Qualifier("businessJdbcTemplate")
    private JdbcTemplate businessJdbcTemplate;
 
    @Autowired
    @Qualifier("systemTransactionManager")
    private PlatformTransactionManager systemTransactionManager;
 
    @Autowired
    @Qualifier("businessTransactionManager")
    private PlatformTransactionManager businessTransactionManager;
 
    @Bean
    public Job myJob() {
        return jobBuilderFactory.get("myJob")
                .start(step1())
                .build();
    }
 
    @Bean
    public Step step1() {
        return stepBuilderFactory.get("step1")
                .<MyEntity, MyEntity>chunk(10)
                .reader(systemItemReader())
                .processor(myProcessor())
                .writer(businessItemWriter())
                .transactionManager(businessTransactionManager)
                .build();
    }
 
    @Bean
    public ItemReader<MyEntity> systemItemReader() {
        JdbcCursorItemReader<MyEntity> reader = new JdbcCursorItemReader<>();
        reader.setDataSource(systemJdbcTemplate.getDataSource());
        reader.setSql("SELECT * FROM SYSTEM_TABLE");
        reader.setRowMapper(new MyEntityMapper());
        return reader;
    }
 
    @Bean
    public ItemProcessor<MyEntity, MyEntity> myProcessor() {
        return new MyEntityProcessor();
    }
 
    @Bean
    public ItemWriter<MyEntity> businessItemWriter() {
        JdbcBatchItemWriter<MyEntity> writer = new JdbcBatchItemWriter<>();
        writer.setDataSource(businessJdbcTemplate.getDataSource());
        writer.setSql("INSERT INTO BUSINESS_TABLE (ID, NAME) VALUES (:id, :name)");
        writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<>());
        return writer;
    }
 
}

这个例子中，Job从系统表读取数据，经过处理后，将结果写入业务表。系统表使用systemDataSource连接，业务表使用businessDataSource连接，每个数据源都有自己的事务管理器和JdbcTemplate。