小编典典

重复的Spring Batch作业实例

spring-boot

我有一个小的示例Spring Batch应用程序,该应用程序在首次启动时可以正常运行,但是每当我关闭该应用程序并重新启动jar时,我总是会收到此错误:

Caused by: org.springframework.dao.DuplicateKeyException: PreparedStatementCallback; SQL [INSERT into BATCH_JOB_INSTANCE(JOB_INSTANCE_ID, JOB_NAME, JOB_KEY, VERSION) values (?, ?, ?, ?)]; Duplicate entry '1' for key 1; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 1

我不确定作业增量器设置是否错误。但是就像我说的那样,我可以启动它,然后使用Web服务url
/jobLauncher.html任意次调用批处理。只有在我关闭应用程序并重新启动它之后,我才收到此错误。它想为作业执行表使用ID
1,但以前的运行中已经有ID 1。

主班

@EnableAutoConfiguration
@ComponentScan
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, new String[]{ "date=" + System.currentTimeMillis() });
    }
}

Web服务类

@Controller
public class JobLauncherController {

    @Autowired
    JobLauncher jobLauncher;

    @Autowired
    Job job;

    @RequestMapping("/jobLauncher.html")
    @ResponseBody
    public String handle() throws Exception{
        jobLauncher.run(job, new JobParametersBuilder().addString("date", System.currentTimeMillis() + "").toJobParameters());
        return "Started the batch...";
    }
}

Spring批处理类

@Configuration
@EnableBatchProcessing
public class SampleBatchApplication {

    @Autowired
    private JobBuilderFactory jobs;

    @Autowired
    private StepBuilderFactory steps;

    @Bean
    protected Tasklet tasklet() {
        return new Tasklet() {
            @Override
            public RepeatStatus execute(StepContribution contribution,
                                        ChunkContext context) {
                return RepeatStatus.FINISHED;
            }
        };
    }

    @Bean
    public Job job() throws Exception {
        return this.jobs.get("job")
                   .incrementer(new RunIdIncrementer())
                   .flow(this.step1())
                   .end()
                   .build();
    }

    @Bean
    protected Step step1() throws Exception {
        return this.steps.get("step1").tasklet(this.tasklet()).build();
    }

    @Bean
    public DataSource dataSource() {

        BasicDataSource ds = new BasicDataSource();

        try {
            ds.setDriverClassName("com.mysql.jdbc.Driver");
            ds.setUsername("test");
            ds.setPassword("test");
            ds.setUrl("jdbc:mysql://127.0.0.1:3306/spring-batch");

        } catch (Exception e) {
            e.printStackTrace();
        }
        return ds;
    }
}

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2020-05-30

共1个答案

小编典典

找到了问题。使用@EnableAutoConfigurationSpring
Boot中的注释时,它将调用org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration类,该类将从’schema-
mysql.sql’文件初始化数据库。

schema-mysql.sql文件内部,有一些代码可以重置批处理元表的序列ID,这就是为什么我遇到重复键错误的原因:

INSERT INTO BATCH_STEP_EXECUTION_SEQ values(0);
INSERT INTO BATCH_JOB_EXECUTION_SEQ values(0);
INSERT INTO BATCH_JOB_SEQ values(0);

解决方法是分别构建Spring Batch表,然后将@EnableAutoConfiguration注释更改为:

@EnableAutoConfiguration(exclude={BatchAutoConfiguration.class})

因此,在应用程序启动时,它将不会尝试初始化Spring Batch表。

要为其他组件排除或自定义Spring
Boot的自动配置,您可以在此处找到一些文档:http :
//projects.spring.io/spring-boot/docs/spring-boot-
autoconfigure/README.html

BatchAutoConfiguration代码:[https](https://github.com/spring-projects/spring-
boot/blob/master/spring-boot-
autoconfigure/src/main/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfiguration.java)
//github.com/spring-projects/spring-boot/blob/master/spring-boot-
autoconfigure/src/main/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfiguration.java
2020-05-30