春季批处理：如何使用平面文件读取CSV文件的页脚并进行验证
我正在使用弹簧批处理和扁平文件条目阅读器来读取.CSV 文件。文件具有页眉（第一行）、详细信息和页脚（最后一行）。因此，我想通过页脚行验证详细信息的总数。
这是我.csv文件的示例。
电影.csv
名称|类型|诺丁山|
浪漫喜剧|1999
年玩具总动员3|动画|2010
美国队长3：第一复仇者|动作|2011
3
从示例文件
第一行是标题（我忽略它）。
第 2-4 行是细节行，最后是页脚。
我想读取页脚并获取值（最后一行= 3），
然后，获取详细信息的总数（在这种情况下，我们有3行），
最后我将验证页脚（3）的总数，详细信息记录的总数（3）是否相等？
这是我的代码。
@Bean
@StepScope
public FlatFileItemReader<Movie> movieItemReader(String filePath) {
FlatFileItemReader<Movie> reader = new FlatFileItemReader<>();
reader.setLinesToSkip(1); //skip header line
reader.setResource(new PathResource(filePath));
DelimitedLineTokenizer tokenizer = new DelimitedLineTokenizer("|");
DefaultLineMapper<Movie> movieLineMapper = new DefaultLineMapper<>();
FieldSetMapper<Movie> movieMapper = movieFieldSetMapper();
movieLineMapper.setLineTokenizer(tokenizer);
movieLineMapper.setFieldSetMapper(movieFieldSetMapper);
movieLineMapper.afterPropertiesSet();
reader.setLineMapper(movieLineMapper);
return reader;
}
public FieldSetMapper<Movie> movieFieldSetMapper() {
BeanWrapperFieldSetMapper<Movie> movieMapper = new BeanWrapperFieldSetMapper<>();
movieMapper.setTargetType(Movie.class);
return movieMapper;
}
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可以使用面向块的步骤作为作业业务逻辑之前的验证步骤。此步骤将使用 a 保存最后一项，使用 a 进行验证。下面是一个快速示例：ItemReadListenerStepExecutionListenerimport org.springframework.batch.core.ExitStatus;import org.springframework.batch.core.ItemReadListener;import org.springframework.batch.core.Job;import org.springframework.batch.core.JobParameters;import org.springframework.batch.core.Step;import org.springframework.batch.core.StepExecution;import org.springframework.batch.core.StepExecutionListener;import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;import org.springframework.batch.core.configuration.annotation.StepScope;import org.springframework.batch.core.launch.JobLauncher;import org.springframework.batch.core.listener.StepExecutionListenerSupport;import org.springframework.batch.item.ItemWriter;import org.springframework.batch.item.file.FlatFileItemReader;import org.springframework.batch.item.file.mapping.PassThroughLineMapper;import org.springframework.batch.repeat.RepeatStatus;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationContext;import org.springframework.context.annotation.AnnotationConfigApplicationContext;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.io.ByteArrayResource;@Configuration@EnableBatchProcessingpublic class MyJob { @Autowired private JobBuilderFactory jobs; @Autowired private StepBuilderFactory steps; @Bean @StepScope public FlatFileItemReader<String> itemReader() { FlatFileItemReader<String> reader = new FlatFileItemReader<>(); reader.setLinesToSkip(1); //skip header line reader.setResource(new ByteArrayResource("header\nitem1\nitem2\n2".getBytes())); reader.setLineMapper(new PassThroughLineMapper()); return reader; } @Bean public ItemWriter<String> itemWriter() { return items -> { for (String item : items) { System.out.println("item = " + item); } }; } @Bean public Step step1() { MyListener myListener = new MyListener(); return steps.get("step1") .<String, String>chunk(5) .reader(itemReader()) .writer(itemWriter()) .listener((ItemReadListener<String>) myListener) .listener((StepExecutionListener) myListener) .build(); } @Bean public Step step2() { return steps.get("step2") .tasklet((contribution, chunkContext) -> { System.out.println("Total count is ok as validated by step1"); return RepeatStatus.FINISHED; }) .build(); } @Bean public Job job() { return jobs.get("job") .start(step1()) .next(step2()) .build(); } static class MyListener extends StepExecutionListenerSupport implements ItemReadListener<String> { private String lastItem; @Override public void beforeRead() { } @Override public void afterRead(String item) { this.lastItem = item; } @Override public void onReadError(Exception ex) { } @Override public ExitStatus afterStep(StepExecution stepExecution) { int readCount = stepExecution.getReadCount(); int totalCountInFooter = Integer.valueOf(this.lastItem); // TODO sanity checks (number format, etc) System.out.println("readCount = " + (readCount - 1)); // substract footer from the read count System.out.println("totalCountInFooter = " + totalCountInFooter); // TODO do validation on readCount vs totalCountInFooter return ExitStatus.COMPLETED; // return appropriate exit status according to validation result } } public static void main(String[] args) throws Exception { ApplicationContext context = new AnnotationConfigApplicationContext(MyJob.class); JobLauncher jobLauncher = context.getBean(JobLauncher.class); Job job = context.getBean(Job.class); jobLauncher.run(job, new JobParameters()); }}此示例打印：item = item1item = item2item = 2readCount = 2totalCountInFooter = 2Total count is ok as validated by step1希望这有帮助。
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