【Spring】SpringBatch自动注入原理

SpringBatch自动注入原理

　　1、需要使用@EnableBatchProcessing注解

　　　　启用批处理功能

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(BatchConfigurationSelector.class)
public @interface EnableBatchProcessing {

    boolean modular() default false;

}

　　2、@EnableBatchProcessing注解导入了类 BatchConfigurationSelector.java

　　3、BatchConfigurationSelector.java导入了 SimpleBatchConfiguration.class

@Configuration
public class SimpleBatchConfiguration extends AbstractBatchConfiguration {

    @Autowired
    private ApplicationContext context;

    // 任务仓库
    @Override
    @Bean
    public JobRepository jobRepository() throws Exception {
        return createLazyProxy(jobRepository, JobRepository.class);
    }

    // 任务启动器
    @Override
    @Bean
    public JobLauncher jobLauncher() throws Exception {
        return createLazyProxy(jobLauncher, JobLauncher.class);
    }

    @Override
    @Bean
    public JobRegistry jobRegistry() throws Exception {
        return createLazyProxy(jobRegistry, JobRegistry.class);
    }

    @Override
    @Bean
    public JobExplorer jobExplorer() {
        return createLazyProxy(jobExplorer, JobExplorer.class);
    }

        ......
}

 

　　4、SimpleBatchConfiguration extends AbstractBatchConfiguration，而AbstractBatchConfiguration如下：

@Configuration
@Import(ScopeConfiguration.class)
public abstract class AbstractBatchConfiguration implements ImportAware {

    @Autowired(required = false)
    private DataSource dataSource;

    private BatchConfigurer configurer;
    
    // 任务工厂
    @Bean
    public JobBuilderFactory jobBuilders() throws Exception {
        return new JobBuilderFactory(jobRepository());
    }

    // 步骤工厂
    @Bean
    public StepBuilderFactory stepBuilders() throws Exception {
        return new StepBuilderFactory(jobRepository(), transactionManager());
    }
        ......
}

 

　　所在使用过程中，可以使用spring自动注入 任务工厂 JobBuilderFactory 和 步骤工厂 StepBuilderFactory

　　5、关于SpringBatch任务，在SpringBoot中启动运行，是因为 BatchAutoConfiguration类 

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ JobLauncher.class, DataSource.class })
@AutoConfigureAfter(HibernateJpaAutoConfiguration.class)
@ConditionalOnBean(JobLauncher.class)
@EnableConfigurationProperties(BatchProperties.class)
@Import(BatchConfigurerConfiguration.class)
public class BatchAutoConfiguration {

    // 在Spring中注入CommandLineRunner，自动运行
    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnProperty(prefix = "spring.batch.job", name = "enabled", havingValue = "true", matchIfMissing = true)
    public JobLauncherCommandLineRunner jobLauncherCommandLineRunner(JobLauncher jobLauncher, JobExplorer jobExplorer,
            JobRepository jobRepository, BatchProperties properties) {
        JobLauncherCommandLineRunner runner = new JobLauncherCommandLineRunner(jobLauncher, jobExplorer, jobRepository);
        String jobNames = properties.getJob().getNames();
        if (StringUtils.hasText(jobNames)) {
            runner.setJobNames(jobNames);
        }
        return runner;
    }
    ......
}