Spring batch to upload a CSV file and insert into database accordingly

Question

My project has this requirement where user uploads a CSV file which has to be pushed to mysql database. I know we can use Spring batch to process large number of records. Bu

Answer 1

Please have this as main reference: http://walkingtechie.blogspot.co.uk/2017/03/spring-batch-csv-file-to-mysql.html This explains how you use Batch to import a CSV file into a MySQL database.

However, as you said, all the example assume an hardcode file which is not what you want.

In the code below, the important bits (that differ from the example in the link I provided) are the Controller that take a multipart file and save it in a temporary folder. Then the file name is passed to the Job as parameter:

JobExecution jobExecution = jobLauncher.run(importUserJob, new JobParametersBuilder()
                .addString("fullPathFileName", fileToImport.getAbsolutePath())
                .toJobParameters());

Finally, the importReader uses the param fullPathFileName to load the file uploaded by the user:

      @Bean
      public FlatFileItemReader<Person> importReader(@Value("#{jobParameters[fullPathFileName]}") String pathToFile) {
        FlatFileItemReader<Person> reader = new FlatFileItemReader<>();
        reader.setResource(new FileSystemResource(pathToFile));

Here the full code (not tested but it has most of the components) to give you an idea:

@Configuration
@EnableBatchProcessing
public class BatchConfig{

    @Bean
    public ResourcelessTransactionManager batchTransactionManager(){
        ResourcelessTransactionManager transactionManager = new ResourcelessTransactionManager();
        return transactionManager;
    }

    @Bean
    protected JobRepository jobRepository(ResourcelessTransactionManager batchTransactionManager) throws Exception{
        MapJobRepositoryFactoryBean jobRepository = new MapJobRepositoryFactoryBean();
        jobRepository.setTransactionManager(batchTransactionManager);
        return (JobRepository)jobRepository.getObject();
    }

    @Bean
    public JobLauncher jobLauncher(JobRepository jobRepository) throws Exception {
        SimpleJobLauncher jobLauncher = new SimpleJobLauncher();
        jobLauncher.setJobRepository(jobRepository);
        return jobLauncher;
    }

}

@Configuration
public class ImportJobConfig {

    @Bean
    public FlatFileItemReader<Person> importReader(@Value("#{jobParameters[fullPathFileName]}") String pathToFile) {
        FlatFileItemReader<Person> reader = new FlatFileItemReader<>();
        reader.setResource(new FileSystemResource(pathToFile));
        reader.setLineMapper(new DefaultLineMapper<Person>() {{
            setLineTokenizer(new DelimitedLineTokenizer() {{
                setNames(new String[]{"firstName", "lastName"});
            }});
            setFieldSetMapper(new BeanWrapperFieldSetMapper<Person>() {{
                setTargetType(Person.class);
            }});
        }});
        return reader;
    }

    @Bean
    public PersonItemProcessor processor() {
        return new PersonItemProcessor();
    }

    @Bean
    public JdbcBatchItemWriter<Person> writer() {
        JdbcBatchItemWriter<Person> writer = new JdbcBatchItemWriter<>();
        writer.setItemSqlParameterSourceProvider(
                new BeanPropertyItemSqlParameterSourceProvider<Person>());
        writer.setSql("INSERT INTO people (first_name, last_name) VALUES (:firstName, :lastName)");
        writer.setDataSource(dataSource);
        return writer;
    }
    // end::readerwriterprocessor[]

    // tag::jobstep[]
    @Bean
    public Job importUserJob(JobCompletionNotificationListener listener) {
        return jobBuilderFactory.get("importUserJob").incrementer(new RunIdIncrementer())
                .listener(listener).flow(step1()).end().build();
    }

    @Bean
    public Step step1(@Qualifier("importReader") ItemReader<Person> importReader) {
        return stepBuilderFactory.get("step1").<Person, Person>chunk(10).reader(importReader)
                .processor(processor()).writer(writer()).build();
    }

}

@RestController
public class MyImportController {

    @Autowired private JobLauncher jobLauncher;
    @Autowired private Job importUserJob;

    @RequestMapping(value="/import/file", method=RequestMethod.POST)
    public String create(@RequestParam("file") MultipartFile multipartFile) throws IOException{

        //Save multipartFile file in a temporary physical folder
        String path = new ClassPathResource("tmpuploads/").getURL().getPath();//it's assumed you have a folder called tmpuploads in the resources folder
        File fileToImport = new File(path + multipartFile.getOriginalFilename());
        OutputStream outputStream = new FileOutputStream(fileToImport);
        IOUtils.copy(multipartFile.getInputStream(), outputStream);
        outputStream.flush();
        outputStream.close();       

        //Launch the Batch Job
        JobExecution jobExecution = jobLauncher.run(importUserJob, new JobParametersBuilder()
                .addString("fullPathFileName", fileToImport.getAbsolutePath())
                .toJobParameters());        

        return "OK";
    }

}

Answer 2

I did it by mixing Spring MVC (RestController) and Spring Batch. Spring MVC helped in uploading the csv file as multipart request.Then asynchronously I called Spring batch by passing this uploaded CSV to the Spring Job. Once Spring job received the csv file then it did spring batch processing by reading, processing and writing to DB job.