我使用的是 Spring Boot Batch 示例。在此示例中，我希望使用FlatFileItemWriter创建CSV文件。 writer.setResource(new ClassPathResource("csv/users.csv"));不允许我创建CSV文件。我怀疑我们需要在此处提供什么额外的参数？
org.springframework.batch.item.ItemStreamException: Could not convert resource to file: [class path resource [csv/users.csv]]
at org.springframework.batch.item.file.FlatFileItemWriter.getOutputState(FlatFileItemWriter.java:399) ~[spring-batch-infrastructure-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.item.file.FlatFileItemWriter.open(FlatFileItemWriter.java:337) ~[spring-batch-infrastructure-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.item.support.CompositeItemStream.open(CompositeItemStream.java:103) ~[spring-batch-infrastructure-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep.open(TaskletStep.java:310) ~[spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:197) ~[spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:66) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:67) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:136) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:308) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:141) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) [spring-core-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:134) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_151]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_151]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_151]
at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_151]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:197) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) [spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) [spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at com.sun.proxy.$Proxy46.run(Unknown Source) [na:na]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:163) [spring-boot-autoconfigure-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:179) [spring-boot-autoconfigure-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:134) [spring-boot-autoconfigure-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:128) [spring-boot-autoconfigure-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:797) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:781) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:335) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
at com.jackrutorial.SpringBatchDatabaseToCsvApplication.main(SpringBatchDatabaseToCsvApplication.java:10) [classes/:na]
Caused by: java.io.FileNotFoundException: class path resource [csv/users.csv] cannot be resolved to URL because it does not exist
at org.springframework.core.io.ClassPathResource.getURL(ClassPathResource.java:195) ~[spring-core-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:129) ~[spring-core-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.batch.item.file.FlatFileItemWriter.getOutputState(FlatFileItemWriter.java:396) ~[spring-batch-infrastructure-4.0.1.RELEASE.jar:4.0.1.RELEASE]
... 35 common frames omitted
这是代码段
@Bean
public FlatFileItemWriter<User> writer() {
FlatFileItemWriter<User> writer = new FlatFileItemWriter<User>();
writer.setResource(new ClassPathResource("csv/users.csv"));
writer.setShouldDeleteIfEmpty(false);
writer.setShouldDeleteIfExists(false);
writer.setLineAggregator(new DelimitedLineAggregator<User>() {
{
setDelimiter(",");
setFieldExtractor(new BeanWrapperFieldExtractor<User>() {
{
setNames(new String[] { "id", "name" });
}
});
}
});
return writer;
}