HowToDoInJava

Spring Batch CSV to Database – Java Annotation Config Example

By | Filed Under: Spring Batch

Learn to use Spring batch to read records from CSV file and insert into database using JdbcBatchItemWriter. I am using embedded database H2 to demo this example.

Table of Contents

Project Overview
Maven Dependencies
CSV Reader and Database Writer Configuration
Configure H2 Database
Demo

Project Overview

In this application, we will perform following tasks:

  1. Read employee records from CSV file with FlatFileItemReader
  2. Configure H2 database and create EMPLOYEE table in it
  3. Write employee records to EMPLOYEE table with JdbcBatchItemWriter
  4. Log items inserted to database using ItemProcessor
  5. Verify inserted records using H2 console

Package Structure

Package Structure

Maven Dependencies

Quickly go through maven dependencies needed to build this example. spring-boot-starter-web is needed to verify data in H2 console from browser window.

<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd;
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.howtodoinjava</groupId>
	<artifactId>App</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>App</name>
	<url>http://maven.apache.org</url>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.3.RELEASE</version>
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-batch</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
			<scope>runtime</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>repository.spring.release</id>
			<name>Spring GA Repository</name>
			<url>http://repo.spring.io/release</url>
		</repository>
	</repositories>
</project>

CSV Reader and Database Writer Configuration

  1. We will use FlatFileItemReader for reading the CSV file. we will use it’s standard configuration involving DefaultLineMapper, DelimitedLineTokenizer and BeanWrapperFieldSetMapper classes.
  2. For writing the records in DB, we will use JdbcBatchItemWriter which is standard writer for executing batch queries in database for Spring batch jobs.
package com.howtodoinjava.demo.config;

import javax.sql.DataSource;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
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.launch.support.RunIdIncrementer;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.database.BeanPropertyItemSqlParameterSourceProvider;
import org.springframework.batch.item.database.JdbcBatchItemWriter;
import org.springframework.batch.item.file.FlatFileItemReader;
import org.springframework.batch.item.file.LineMapper;
import org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper;
import org.springframework.batch.item.file.mapping.DefaultLineMapper;
import org.springframework.batch.item.file.transform.DelimitedLineTokenizer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
import com.howtodoinjava.demo.model.Employee;

@Configuration
@EnableBatchProcessing
public class BatchConfig {
	
	@Autowired
	private JobBuilderFactory jobBuilderFactory;

	@Autowired
	private StepBuilderFactory stepBuilderFactory;

	@Value("classPath:/input/inputData.csv")
	private Resource inputResource;

	@Bean
	public Job readCSVFileJob() {
		return jobBuilderFactory
				.get("readCSVFileJob")
				.incrementer(new RunIdIncrementer())
				.start(step())
				.build();
	}

	@Bean
	public Step step() {
		return stepBuilderFactory
				.get("step")
				.<Employee, Employee>chunk(5)
				.reader(reader())
				.processor(processor())
				.writer(writer())
				.build();
	}
	
	@Bean
    public ItemProcessor<Employee, Employee> processor() {
        return new DBLogProcessor();
    }
	
	@Bean
	public FlatFileItemReader<Employee> reader() {
		FlatFileItemReader<Employee> itemReader = new FlatFileItemReader<Employee>();
		itemReader.setLineMapper(lineMapper());
		itemReader.setLinesToSkip(1);
		itemReader.setResource(inputResource);
		return itemReader;
	}

	@Bean
	public LineMapper<Employee> lineMapper() {
		DefaultLineMapper<Employee> lineMapper = new DefaultLineMapper<Employee>();
		DelimitedLineTokenizer lineTokenizer = new DelimitedLineTokenizer();
		lineTokenizer.setNames(new String[] { "id", "firstName", "lastName" });
		lineTokenizer.setIncludedFields(new int[] { 0, 1, 2 });
		BeanWrapperFieldSetMapper<Employee> fieldSetMapper = new BeanWrapperFieldSetMapper<Employee>();
		fieldSetMapper.setTargetType(Employee.class);
		lineMapper.setLineTokenizer(lineTokenizer);
		lineMapper.setFieldSetMapper(fieldSetMapper);
		return lineMapper;
	}

	@Bean
	public JdbcBatchItemWriter<Employee> writer() {
		JdbcBatchItemWriter<Employee> itemWriter = new JdbcBatchItemWriter<Employee>();
		itemWriter.setDataSource(dataSource());
		itemWriter.setSql("INSERT INTO EMPLOYEE (ID, FIRSTNAME, LASTNAME) VALUES (:id, :firstName, :lastName)");
		itemWriter.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<Employee>());
		return itemWriter;
	}
	
	@Bean
	public DataSource dataSource(){
		EmbeddedDatabaseBuilder embeddedDatabaseBuilder = new EmbeddedDatabaseBuilder();
		return embeddedDatabaseBuilder.addScript("classpath:org/springframework/batch/core/schema-drop-h2.sql")
				.addScript("classpath:org/springframework/batch/core/schema-h2.sql")
				.addScript("classpath:employee.sql")
				.setType(EmbeddedDatabaseType.H2)
				.build();
	}
}

Also create DBLogProcessor which will log the employee records before writing to database. It’s optional.

package com.howtodoinjava.demo.config;

import org.springframework.batch.item.ItemProcessor;
import com.howtodoinjava.demo.model.Employee;

public class DBLogProcessor implements ItemProcessor<Employee, Employee>
{
	public Employee process(Employee employee) throws Exception
	{
		System.out.println("Inserting employee : " + employee);
		return employee;
	}
}

Model class

package com.howtodoinjava.demo.config;
package com.howtodoinjava.demo.model;

public class Employee {

	String id;
	String firstName;
	String lastName;

	//Setter and getter methods
}

Application properties

#Disable batch job's auto start 
spring.batch.job.enabled=false
spring.main.banner-mode=off

#batch input files location
input.dir=c:/temp/input

Logging configuration

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true">

	<appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
		<encoder>
			<charset>UTF-8</charset>
			<Pattern>%d{yyyy-MM-dd HH:mm:ss} %p %X{TXNID} - %m%n</Pattern>
		</encoder>
	</appender>

	<root level="INFO">
		<appender-ref ref="consoleAppender" />
	</root>
</configuration>

Configure H2 Database

We have already configured the datasource in BatchConfig.java.

@Bean
public DataSource dataSource(){
	EmbeddedDatabaseBuilder embeddedDatabaseBuilder = new EmbeddedDatabaseBuilder();
	return embeddedDatabaseBuilder.addScript("classpath:org/springframework/batch/core/schema-drop-h2.sql")
			.addScript("classpath:org/springframework/batch/core/schema-h2.sql")
			.addScript("classpath:employee.sql")
			.setType(EmbeddedDatabaseType.H2)
			.build();
}

Create EMPLOYEE table

Above configuration will generate default tables automatically. To generate EMPLOYEE table, create schema file employee.sql and put in resources folder.

DROP TABLE EMPLOYEE IF EXISTS;

CREATE TABLE EMPLOYEE  (
	ID VARCHAR(10),  
	FIRSTNAME VARCHAR(100),  
	LASTNAME VARCHAR(100) 
) ;

Enable H2 Console

To enable H2 console, register org.h2.server.web.WebServlet with with Spring web.

package com.howtodoinjava.demo.config;

import org.h2.server.web.WebServlet;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@SuppressWarnings({"rawtypes","unchecked"})
@Configuration
public class WebConfig {
	
	@Bean
    ServletRegistrationBean h2servletRegistration(){
		ServletRegistrationBean registrationBean = new ServletRegistrationBean( new WebServlet());
        registrationBean.addUrlMappings("/console/*");
        return registrationBean;
    }
}

Demo

Our application configuration is done and Job is ready to be executed. Let’s create input CSV file.

id,firstName,lastName
1,Lokesh,Gupta
2,Amit,Mishra
3,Pankaj,Kumar
4,David,Miller
5,David,Walsh

Run the demo

To run the demo and batch job, create Spring boot application class and start application.

package com.howtodoinjava.demo;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;

@SpringBootApplication
@EnableScheduling
public class App
{
    @Autowired
    JobLauncher jobLauncher;
     
    @Autowired
    Job job;
     
    public static void main(String[] args)
    {
        SpringApplication.run(App.class, args);
    }
     
    @Scheduled(cron = "0 */1 * * * ?")
    public void perform() throws Exception
    {
        JobParameters params = new JobParametersBuilder()
                .addString("JobID", String.valueOf(System.currentTimeMillis()))
                .toJobParameters();
        jobLauncher.run(job, params);
    }
}

Verify batch job results

To verify the successful batch job execution, check the logs and the H2 console.

2018-07-11 19:11:00 INFO  - Job: [SimpleJob: [name=readCSVFileJob]] launched with the following parameters: [{JobID=1531316460004}]

2018-07-11 19:11:00 INFO  - Executing step: [step]

Inserting employee : Employee [id=1, firstName=Lokesh, lastName=Gupta]
Inserting employee : Employee [id=2, firstName=Amit, lastName=Mishra]
Inserting employee : Employee [id=3, firstName=Pankaj, lastName=Kumar]
Inserting employee : Employee [id=4, firstName=David, lastName=Miller]
Inserting employee : Employee [id=5, firstName=David, lastName=Walsh]

2018-07-11 19:11:00 INFO  - Job: [SimpleJob: [name=readCSVFileJob]] completed with the following parameters: [{JobID=1531316460004}] and the following status: [COMPLETED]

H2 Console

H2 Console Login
H2 Console Login
Data in H2 Console
Data in H2 Console

Drop me your questions in comments section.

Happy Learning !!

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Feedback, Discussion and Comments

  1. followed the same example but the records are not being sent to the h2 database. is there anything that is missing

    Reply

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