How to read from application.properties and set as Job Parameter in Spring Batch

Question

I want to read from my application.properties , the input and output paths for my Spring Batch application, and set them to the jobParametersBuilder, so I can access them throughout the job execution (to assign them to readers and writers).

I was able to read from the application.properties in other configuration classes, but I can't seem to achieve doing it inside my main class. I need to do it here in order to be able to assign the value to the Job Parameters, before executing the job.

My Main Class:

@SpringBootApplication
public class GleBatchApplication {


 private static final Logger logger = 
 LogManager.getLogger(FormateadorJobConfig.class);

    @Value("${file.input}")
    private static String inputPath;

    @Value("${file.output}")
    private static String outputPath;


public static void main(String[] args) throws JobExecutionAlreadyRunningException, JobRestartException, JobInstanceAlreadyCompleteException, JobParametersInvalidException {


     ApplicationContext ctx = SpringApplication.run(GleBatchApplication.class, args);

     JobLauncher lanzadorJob = ctx.getBean(JobLauncher.class);
     Job jobFormateador = ctx.getBean("jobFormateador", Job.class);
     JobParameters jobParameters = new JobParametersBuilder().
             addLong("Time in miliseconds: ", System.currentTimeMillis())
             .addString("inputPath", inputPath)
             .addString("outputPath", outputPath)
             .toJobParameters();

        System.out.println("Valor leido del properties: " + inputPath);
        System.out.println("Valor leido del properties: " + outputPath);


     JobExecution jobExecution = lanzadorJob.run(jobFormateador, jobParameters);
     logger.info("=================================================");
     logger.info("START TIME: " + jobExecution.getCreateTime());
     logger.info("FINISH TIME: " + jobExecution.getEndTime());
     logger.info("=================================================");

My application.properties file:

spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url = 
jdbc:mysql://localhost:3306/curso_batch_multiplefilewriting_2? 
autoReconnect=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.platform=mysql
spring.datasource.continueOnError=false

spring.batch.job.enabled=false


file.input = /inputFiles/GLEO-MN170100-PROCESO01-SUBDFACT-000001.txt
file.output = outputFiles/GLEO-MN1701-PROCESO001-SUBDFACT-FORMATDO-000001.txt

Also I have tried doing a separate configuration class, for the input and output, but i dont understand how to call it from my main class:

InOutConfiguration:

@Configuration
@PropertySource("classpath:application.properties")
public class InOutConfiguration {

@Value("${file.input}")
 private  String inputPath;

@Value("${file.output}")
 private  String outputPath;


@Bean
  public static PropertySourcesPlaceholderConfigurer   propertySourcesPlaceholderConfigurer() {
      return new PropertySourcesPlaceholderConfigurer();
  }

public  String getInputPath() {
    return inputPath;
}

public  void setInputPath(String inputPath) {
    this.inputPath = inputPath;
}

public  String getOutputPath() {
    return outputPath;
}

public  void setOutputPath(String outputPath) {
    this.outputPath = outputPath;
}

}

I'm getting inputPath = null , and outputPath = null.

Answer 1

The below code works (I believe you have your application.properties file in src/main/resources):

            Properties properties = new Properties();
            InputStream file = null;
            try {
                file = GleBatchApplication.class.getClassLoader().getResourceAsStream("application.properties");
                properties.load(file);
            }catch(Exception e) {
                //exception handling
            }

Place it in your main method and you can read the values from the "properties" variable. Like: properties.getProperty("spring.datasource.driverClassName");

Or you can place the above code in a different class and call the method to get properties. SO that you can use it where ever you want.