A CSV file containing data needs to be converted as XML along with the data and tags will be named after the column name. Below are the important tools and libraries used for spring batch example. Apache Maven 3.5.0 – for project build and dependencies management. Eclipse Oxygen Release 4.7.0 – IDE for creating spring batch maven application. Spring-batch compositeWriter sample. GitHub Gist: instantly share code, notes, and snippets. Spring Batch can use different data sources as input to batch processes. Data sources correspond to flat files, XML, and JavaScript Serialized Object Notation (JSON). Spring Batch also supports other types of data sources, such as Java Message Service (JMS), in the message-oriented middleware world. In some cases, the Spring Batch built-in. Step by Step Spring Batch Tutorial with an example. As part of the demo, we will be uploading a csv file through Spring Batch Framework. So to start with, create the spring project and add the following dependency: implementation 'org.springframework.boot:spring-boot-starter-batch'. This is the main dependency of our project. In this tutorial we will discuss about the three most important interfaces of spring batch and an overview of Spring Batch item reader and writer with a sample application. One of the important goals of a batch processing framework is to read large amounts of data, perform some business processing/transformation and write out the result. Spring Batch Framework supports this bulk reading.

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Spring Batch Flat File Item Writer Example Program

What is Spring Batch

Spring Batch is an open-source lightweight and comprehensive batch framework designed to develop batch applications that can process high volume of data.

Spring Batch provides the necessary classes and APIs supporting the following items:

Transaction management
Chunk based processing
Declarative I/O to read and write resources
Start/Stop/Restart
Retry/Skip
Web based administration interface (With Spring Batch Admin)

Spring Batch can execute a sequence of Jobs. A job consists of many steps that can be chained together. There are two types of steps:

READ-PROCESS-WRITE steps : They consist of reading data for a source (Database, File, etc), process that data and finally write it to a resources (Database, File, etc).
Use case examples :
- Read data from MySQL database, process it and write it to CSV file.
- Read Data from files in Folder A, process it, and write data to folder B .
Tasklets or Single Task: Consists of a sigle task. Use case examples can be:
- Send newsletter to subscribers
- Clean up a folder

How to define jobs and tasks

In Spring Batch we can use Annotations or Config files to define jobs and tasks sequence.

Here is an example of configuration using XML :

Use case example

In this example, we will use Spring Batch to read data from a MySql database, process it , and finally write it to a CSV file.

For this tutorial, we will be using the following versions :

spring-core : 4.3.10.RELEASE, Spring framework core
spring-batch-core: 3.0.8.RELEASE, Spring Batch core
mysql-connector-java: 5.1.22 : Contains My SQL driver and other utility classes
spring-jdbc: 4.3.10.RELEASE, to support the communication between Spring Batch and MySQL
Eclipse EDI: Neon 4.6.2
Maven : Apache Maven 3.0.5

the pom.xml file

Database structure and data

For the example we will create a products table and populate it with some data using the following script.

The Project XML Configuration

As mentioned before, we can do the same configuration using Annotations. for this example, we will be using xml files to configure Spring Batch.

XML configuration can be written into the same file, however it is a good practice to separate them (Spring context, Data sources and jobs description ).

The datasource.xml file

This file contains the information of the datasource used to comunicate with the database.

The spring-context.xml file

This file contains the Spring context configuration.

The job-products.xml file

This file contains the jobs and tasks definition. It does also include the two previous xml files.

The file declares also all the beans used by the jobs.

product: A reference to the Product Transfer/Value Bean.
itemProcessor: A Reference to class responsible for processing items
jobListener : A Refernece to the class responsible for listening to job processing events.
productItemReader: A reference to the class responsible for reading data from the database.
productFlatFileItemWriter: A reference to the class responsible for writing data to csv files.

The xml above make references to the following classes we created for this example.

Project source code

The Product Bean

Represents a product

The Product mapper

This class must implement the RowMapper Class and override the rowMap() method. It is responsible for converting a ResultSet row to a Product object.

The Item Processor

This object processes an item retrieved from the database. It must implement the ItemProcessor interface and override the process() method.

The Job Listener

This object is responsible for listening to items processing events. It must implement the JobExecutionListener and override the beforeJob() and afterJob() methods.

The Main program

This class executes the job. It references the Spring Batch context file (job-products.xml).

Project structure

Finally and to recapitulate, the project structure will look like the following.

Execution results

The execution of the code will print the following trace on the console.

And generate an xml file with the following content:

Phone|300.0|50
Tablet|250.0|20
Mouse|20.0|30
Keyboard|20.0|30
Speaker|40.0|30
Screen|300.0|40

I’m going to show you exactly how to create a Spring BatchHello World example that uses Spring Boot.

(Step-by-step)

So if you’re a Spring Batch beginner, you’ll love this guide.

Ready?

If you want to learn more about Spring Batch - head on over to the Spring Batch tutorials page.

1. How Does the Spring Batch Framework Work?

Before we dive into the code let’s look at the Spring Batch framework. It contains the following key building blocks:

A batch process consists of a Job. This is an entity that encapsulates the entire batch process.

A Job can consist of one or more Steps. In most cases, a step will read data (via an ItemReader), process it (using an ItemProcessor) and then write it (via an ItemWriter).

The JobLauncher handles launching a Job.

And finally the JobRepository stores metadata about configured and executed Jobs.

To show how Spring Batch works let’s build a simple Hello World batch job.

In the example, we read a person’s first and last name from a person.csv file. From this data, a greeting is generated. This greeting is then written to a greetings.txt file.

2. General Project Overview

We will use the following tools/frameworks:

Spring Batch 4.1
Spring Boot 2.1
Maven 3.6

Our project has the following directory structure:

3. Maven Setup

We build and run our example using Maven. If not already the case, download and install Apache Maven.

Let’s use Spring Initializr to generate our Maven project. Make sure to select Batch as a dependency.

Click Generate Project to generate and download the Spring Boot project template. At the root of the project, you’ll find a pom.xml file which is the XML representation of the Maven projec

Spring Batch Flat File Item Writer Example