Spring Batch Examples - Read from DB Paging

Project with examples using Spring Batch.

In this project there are configurations using JdbcPagingItemReader and ItemWriter simple implementation to write a log.

Requirements

You must set a database used for tests in our example we are using Postgresql. Below you can find a command line with docker.

docker run -d --name postgres -p 5432:5432 -e POSTGRES_PASSWORD=postgres -v [local-directory-here]:/var/lib/postgresql/data postgres:10.10

• Java 11
• Maven 3.5.* or higher
• Make sure your workspace is using encode UTF-8
• The Lombok library is being used as a resource to help the creation of classes, check if your IDE has support/plugin to use Lombok. More information at https://projectlombok.org.

Initialize the Spring Batch database model

At application.properties file in the src / main / resources folder there is the parameter below that is commented by default, in the first time you run a spring batch with a empty database you need to create the data model of Spring Batch repository.

spring.batch.initialize-schema=always

Getting Started

Reference documentation

For further reference, please consider the following sections:

• Official Apache Maven documentation
• Spring Boot Maven Plugin Reference Guide
• Spring Batch

Guides

The guides below illustrate how to correctly use some spring batch features:

• Creating a Batch Service

Environment variables

The application.properties file in the src / main / resources folder contains the environment variables that will be used by the application. If no environment variable is informed, the deafult values ​​will be used. Description of the variables:

• REPOSITORY_DRIVER: (spring.datasource.driverClassName) Driver used to connect to the Spring Batch repository database. The default value is: org.h2.Driver, referring to database h2 in memory.
• REPOSITORY_URL: (spring.datasource.url) Connection sring to the Spring Batch repository database. The default value is: jdbc:h2:mem:springbatch.
• REPOSITORY_USER: (spring.datasource.username) User connecting to the Spring Batch repository database. The default value is: sa.
• REPOSITORY_PASS: (spring.datasource.password) Password for connecting to the Spring Batch repository database. The default value is: .

Running the project with docker

The maven Jib plugin builds a Docker image. To create an image, execute the command below replacing the variable {imageName} with the name of the image to be generated. Jib will use the local Docker daemon:

mvn clean package jib:dockerBuild -Dimage={imageName}

To run the job using docker, run the command below:

docker run -it -e {environment variable}={environment variable value} {imageName} {job parameter}={job parameter value}