CODEWITHSUNDEEP
javaspringspring-batch
Nimchip
Nimchip

Reputation: 1735

How could I assign dynamic properties to a Spring Batch configuration?

I have a use case where I need to dynamically change the resource, the column names, positions of the columns, and other stuff in the Spring Batch configuration bean. The jobs will be launched from a JobLauncher.

I have constructed the following:

@Configuration
@EnableBatchProcessing
public class BatchConfiguration {

    public JobBuilderFactory jobBuilderFactory;
    public StepBuilderFactory stepBuilderFactory;

    //these are the properties i need to dynamically change
    private String[] names;
    private Resource inputResource;
    private String[] positions;
    private String tableName;
    private String columnNames;
    private String values;

    @Autowired
    public void setJobBuilderFactory(JobBuilderFactory jobBuilderFactory) {
        this.jobBuilderFactory = jobBuilderFactory;
    }

    @Autowired
    public void setStepBuilderFactory(StepBuilderFactory stepBuilderFactory) {
        this.stepBuilderFactory = stepBuilderFactory;
    }

    @Bean
    BatchConfigurer configurer(@Qualifier("prestagingJpaDataSource") DataSource dataSource){
        return new DefaultBatchConfigurer(dataSource);
    }


    @Bean
    public FlatFileItemReader<String[]> reader() {

        return new FlatFileItemReaderBuilder<String[]>()
                .name("hacReader")
                //put file here
                .resource(inputResource)
                .lineMapper(new DefaultLineMapper<String[]>() {{
                    setLineTokenizer(new DelimitedLineTokenizer() {{
                        //put column names here
                        setNames(names);
                    }});
                    //put column positions here
                    setFieldSetMapper(fieldSet -> positions);
                }})
                .build();
    }

    //this is obviously wrong, as i would need to use an ItemPreparedStatementSetter
    @Bean
    public JdbcBatchItemWriter<String[]> writer(DataSource dataSource) {
        return new JdbcBatchItemWriterBuilder<String[]>()
                .itemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<>())
                .sql("INSERT INTO " + tableName + " (" + columnsNames + ") VALUES (" + values)
                .dataSource(dataSource)
                .build();
    }

    @Bean
    public Job importUserJob(JobCompletionNotificationListener listener, Step step1) {
        return jobBuilderFactory.get("importUserJob")
                .incrementer(new RunIdIncrementer())
                .listener(listener)
                .flow(step1)
                .end()
                .build();
    }

    @Bean
    public Step step1(JdbcBatchItemWriter<String[]> writer) {
        return stepBuilderFactory.get("step1")
                .<String[], String[]> chunk(10)
                .reader(reader())
                //.processor(processor())
                .writer(writer)
                .build();
    }
}

Is something like this possible with Spring Batch? These are properties that will vary always so I absolutely cannot have any hard-coded values.

If yes, then what would I need to do to make them work?

Upvotes: 1

Views: 4568

Answers (1)

Mahmoud Ben Hassine
Mahmoud Ben Hassine

Reputation: 31745

You can do that by passing these properties as job parameters (those are best passed as non-identifying job parameters in this case) and late-bind them in your reader at runtime. Here is an example:

@Bean
@StepScope
public ItemReader<String[]> itemReader(
        @Value("#{jobParameters['fileName']}") String fileName,
        @Value("#{jobParameters['columnNames']}") String columnNames
        ) {
    return new FlatFileItemReaderBuilder<String[]>()
            .name("hacReader")
            //put file here
            .resource(new FileSystemResource(fileName))
            .lineMapper(new DefaultLineMapper<String[]>() {{
                setLineTokenizer(new DelimitedLineTokenizer() {{
                    //put column names here
                    setNames(columnNames.split(","));
                }});
            }})
            .build();
}

With this setup, the reader will be dynamically configured with the fileName and columnNames specified as job parameters:

JobParameters jobParameters = new JobParametersBuilder()
            .addString("fileName", "/path/to/input/file")
            .addString("columnNames", "column1,column2,column5")
            .toJobParameters();

Hope this helps.

Upvotes: 2

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