Question

我有一个Spring批处理作业，第一步是读取文件并写入数据库。如果文件不存在，我希望系统等待x分钟，然后重试步骤到y次尝试。我怎样才能做到这一点？

详情

ItemReader如下：

 @Bean
    public ItemReader<Car> reader(LineMapper<Car> lineMapper, File file) {
        FlatFileItemReader<Car> flatFileItemReader = new FlatFileItemReader<Car>();
        flatFileItemReader.setResource(new FileSystemResource(file));
        final int NUMBER_OF_HEADER_LINES = 1;
        flatFileItemReader.setLinesToSkip(NUMBER_OF_HEADER_LINES);
        flatFileItemReader.setLineMapper(lineMapper);
        return flatFileItemReader;
    }

目前，如果file不存在，则抛出以下异常并且作业失败。

2016-08-05 09:30:10.277 ERROR 7668 --- [           main] o.s.batch.core.step.AbstractStep         : Encountered an error executing step stepLoadFile in job testJob

org.springframework.batch.item.ItemStreamException: Failed to initialize the reader
    at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.open(AbstractItemCountingItemStreamItemReader.java:147) ~[spring-batch-infrastructure-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.item.support.CompositeItemStream.open(CompositeItemStream.java:96) ~[spring-batch-infrastructure-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.step.tasklet.TaskletStep.open(TaskletStep.java:310) ~[spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:197) ~[spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:392) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:135) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:306) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) [spring-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_91]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_91]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_91]
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) [spring-batch-core-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at com.sun.proxy.$Proxy78.run(Unknown Source) [na:na]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:215) [spring-boot-autoconfigure-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:232) [spring-boot-autoconfigure-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:124) [spring-boot-autoconfigure-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:118) [spring-boot-autoconfigure-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:804) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:788) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.afterRefresh(SpringApplication.java:775) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.doRun(SpringApplication.java:366) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:305) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1124) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1113) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at com.myorg.LoadApplication.main(LoadApplication.java:15) [bin/:na]
Caused by: java.lang.IllegalStateException: Input resource must exist (reader is in 'strict' mode): file [C:\test\TestData.csv]
    at org.springframework.batch.item.file.FlatFileItemReader.doOpen(FlatFileItemReader.java:251) ~[spring-batch-infrastructure-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.open(AbstractItemCountingItemStreamItemReader.java:144) ~[spring-batch-infrastructure-3.0.6.RELEASE.jar:3.0.6.RELEASE]
    ... 33 common frames omitted

com.myorg.LoadApplication代码启动批处理应用程序，并且是：

@SpringBootApplication
public class LoadApplication {

    public static void main(String[] args) {
        SpringApplication.run(LoadApplication.class, args);
    }

}

更新

在阅读dimitrisli回答之后，我在我的@Configuration课程中尝试了这一点（注意：我还在配置类中添加了@EnableRetry）：

@Bean
public ItemReader<Test> reader(LineMapper<Test> lineMapper, ApplicationProperties properties) {
    FlatFileItemReader<Test> flatFileItemReader = new FlatFileItemReader<Test>() {
        @Override
        @Retryable(value = {ItemStreamException.class}, maxAttempts=5)
        public void open(ExecutionContext executionContext) throws ItemStreamException {
            super.open(executionContext);
        }

        @Override
        @Retryable(maxAttempts=5)
        public Holding read() throws UnexpectedInputException, ParseException, Exception {
            return super.read();
        }

    };
    flatFileItemReader.setResource(new FileSystemResource(properties.getLoadFile()));
    flatFileItemReader.setLineMapper(lineMapper);
    return flatFileItemReader;
}

抛出

ItemStreamException，应用程序退出而不重试。我怎样才能让它重试？

Answer 1

使用Spring Retry，来自Spring Batch的独立衍生项目：假设可能会抛出异常，您想要恢复并重试，比如5次，是ItemStreamException那么你将必须修饰可能抛出此异常的方法：

@Retryable(value = {ItemStreamException.class}, maxAttempts = 5)
public void myMethod() {
   //..
}

Answer 2

您应该使用spring-retry。

RetryTemplate与TimeoutRetryPolicy的组合将允许您编写所需的功能。

您需要将@EnableRetry添加到配置类，并将@Retryable添加到方法中。

在启动应用程序之前，是否需要首先实例化ItemReader？如果不是，您应该只创建bean并在上下文刷新后使用另一个方法初始化它。

Spring Batch - 要读取的文件不可用

2 个答案: