Batch Service is a process to execute more than one command in a single task. In this chapter, you are going to learn how to create batch service in a Spring Boot application.

Let us consider an example where we are going to save the CSV file content into HSQLDB.

To create a Batch Service program, we need to add the Spring Boot Starter Batch dependency and HSQLDB dependency in our build configuration file.

Maven users can add the following dependencies in pom.xml file.

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-batch</artifactId></dependency><dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId></dependency>

Gradle users can add the following dependencies in build.gradle file.

compile(“org.springframework.boot:spring-boot-starter-batch”)compile(“org.hsqldb:hsqldb”)

Now, add the simple CSV data file under classpath resources – src/main/resources and name the file as file.csv as shown −

William,JohnMike, SebastianLawarance, Lime

Next, write a SQL script for HSQLDB – under the classpath resource directory – request_fail_hystrix_timeout

DROP TABLE USERS IF EXISTS;CREATE TABLE USERS ( user_id BIGINT IDENTITY NOT NULL PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20));

Create a POJO class for USERS model as shown −

package com.tecklearn.batchservicedemo;public class User { private String lastName; private String firstName; public User() { } public User(String firstName, String lastName) { this.firstName = firstName; this.lastName = lastName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } @Override public String toString() { return “firstName: ” + firstName + “, lastName: ” + lastName; } }

Now, create an intermediate processor to do the operations after the reading the data from the CSV file and before writing the data into SQL.

package com.tecklearn.batchservicedemo; import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.batch.item.ItemProcessor; public class UserItemProcessor implements ItemProcessor<User, User> { private static final Logger log = LoggerFactory.getLogger(UserItemProcessor.class); @Override public User process(final User user) throws Exception { final String firstName = user.getFirstName().toUpperCase(); final String lastName = user.getLastName().toUpperCase(); final User transformedPerson = new User(firstName, lastName); log.info(“Converting (” + user + “) into (” + transformedPerson + “)”); return transformedPerson; }}

Let us create a Batch configuration file, to read the data from CSV and write into the SQL file as shown below. We need to add the @EnableBatchProcessing annotation in the configuration class file. The @EnableBatchProcessing annotation is used to enable the batch operations for your Spring Boot application.

package com.tecklearn.batchservicedemo; 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.database.BeanPropertyItemSqlParameterSourceProvider;import org.springframework.batch.item.database.JdbcBatchItemWriter;import org.springframework.batch.item.file.FlatFileItemReader;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.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.io.ClassPathResource; @Configuration@EnableBatchProcessingpublic class BatchConfiguration { @Autowired public JobBuilderFactory jobBuilderFactory; @Autowired public StepBuilderFactory stepBuilderFactory; @Autowired public DataSource dataSource; @Bean public FlatFileItemReader<User> reader() { FlatFileItemReader<User> reader = new FlatFileItemReader<User>(); reader.setResource(new ClassPathResource(“file.csv”)); reader.setLineMapper(new DefaultLineMapper<User>() { { setLineTokenizer(new DelimitedLineTokenizer() { { setNames(new String[] { “firstName”, “lastName” }); } }); setFieldSetMapper(new BeanWrapperFieldSetMapper<User>() { { setTargetType(User.class); } }); } }); return reader; } @Bean public UserItemProcessor processor() { return new UserItemProcessor(); } @Bean public JdbcBatchItemWriter<User> writer() { JdbcBatchItemWriter<User> writer = new JdbcBatchItemWriter<User>(); writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<User>()); writer.setSql(“INSERT INTO USERS (first_name, last_name) VALUES (:firstName, :lastName)”); writer.setDataSource(dataSource); return writer; } @Bean public Job importUserJob(JobCompletionNotificationListener listener) { return jobBuilderFactory.get(“importUserJob”).incrementer( new RunIdIncrementer()).listener(listener).flow(step1()).end().build(); } @Bean public Step step1() { return stepBuilderFactory.get(“step1”).<User, User>chunk(10).reader(reader()).processor(processor()).writer(writer()).build(); }}

The reader() method is used to read the data from the CSV file and writer() method is used to write a data into the SQL.

Next, we will have to write a Job Completion Notification Listener class – used to notify after the Job completion.

package com.tecklearn.batchservicedemo; import java.sql.ResultSet;import java.sql.SQLException;import java.util.List; import org.slf4j.Logger;import org.slf4j.LoggerFactory; import org.springframework.batch.core.BatchStatus;import org.springframework.batch.core.JobExecution;import org.springframework.batch.core.listener.JobExecutionListenerSupport;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;import org.springframework.jdbc.core.RowMapper;import org.springframework.stereotype.Component; @Componentpublic class JobCompletionNotificationListener extends JobExecutionListenerSupport { private static final Logger log = LoggerFactory.getLogger(JobCompletionNotificationListener.class); private final JdbcTemplate jdbcTemplate; @Autowired public JobCompletionNotificationListener(JdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; } @Override public void afterJob(JobExecution jobExecution) { if (jobExecution.getStatus() == BatchStatus.COMPLETED) { log.info(“!!! JOB FINISHED !! It’s time to verify the results!!”); List<User> results = jdbcTemplate.query( “SELECT first_name, last_name FROM USERS”, new RowMapper<User>() { @Override public User mapRow(ResultSet rs, int row) throws SQLException { return new User(rs.getString(1), rs.getString(2)); } }); for (User person : results) { log.info(“Found <” + person + “> in the database.”); } } }}

Now, create an executable JAR file, and run the Spring Boot application by using the following Maven or Gradle commands.

For Maven, use the command as shown −

mvn clean install

After “BUILD SUCCESS”, you can find the JAR file under the target directory.

For Gradle, you can use the command as shown −

gradle clean build

After “BUILD SUCCESSFUL”, you can find the JAR file under the build/libs directory.

Run the JAR file by using the command given here −

java –jar <JARFILE>

You can see the output in console window as shown −

So, this brings us to the end of blog. This Tecklearn ‘Spring Boot – Batch Service’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn Spring Boot and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

https://www.tecklearn.com/course/java-and-jee-training/

Java and JEE Training

About the Course

Java and JEE Certification Training is designed by professionals as per the industrial requirements and demands. This training encompasses comprehensive knowledge on basic and advanced concepts of core Java & J2EE along with popular frameworks like Hibernate, Spring & SOA. In this course, you will gain expertise in concepts like Java Array, Java OOPs, Java Function, Java Loops, Java Collections, Java Thread, Java Servlet, and Web Services using industry use-cases and this will help you to become a certified Java expert.

Why Should you take Java and JEE Training?

Java developers are in great demand in the job market. With average pay going between $90,000/- to $120,000/- depending on your experience and the employers.
Used by more than 10 Million developers worldwide to develop applications for 15 Billion devices.
Java is one of the most popular programming languages in the software world. Rated #1 in TIOBE Popular programming languages index (15th Consecutive Year)

What you will Learn in this Course?

Introduction to Java

Java Fundamentals
Introduction to Java Basics
Features of Java
Various components of Java language
Benefits of Java over other programming languages
Key Benefits of Java

Installation and IDE’s for Java Programming Language

Installation of Java
Setting up of Eclipse IDE
Components of Java Program
Editors and IDEs used for Java Programming
Writing a Simple Java Program

Data Handling and Functions

Data types, Operations, Compilation process, Class files, Loops, Conditions
Using Loop Constructs
Arrays- Single Dimensional and Multi-Dimensional
Functions
Functions with Arguments

OOPS in Java: Concept of Object Orientation

Object Oriented Programming in Java
Implement classes and objects in Java
Create Class Constructors
Overload Constructors
Inheritance
Inherit Classes and create sub-classes
Implement abstract classes and methods
Use static keyword
Implement Interfaces and use it

Polymorphism, Packages and String Handling

Concept of Static and Run time Polymorphism
Function Overloading
String Handling –String Class
Java Packages

Exception Handling and Multi-Threading

Exception handling
Various Types of Exception Handling
Introduction to multi-threading in Java
Extending the thread class
Synchronizing the thread

File Handling in Java

Input Output Streams
Java.io Package
File Handling in Java

Java Collections

Wrapper Classes and Inner Classes: Integer, Character, Boolean, Float etc
Applet Programs: How to write UI programs with Applet, Java.lang, Java.io, Java.util
Collections: ArrayList, Vector, HashSet, TreeSet, HashMap, HashTable

Java Database Connectivity (JDBC)

Introduction to SQL: Connect, Insert, Update, Delete, Select
Introduction to JDBC and Architecture of JDBC
Insert/Update/Delete/Select Operations using JDBC
Batch Processing Transaction
Management: Commit and Rollback

Java Enterprise Edition – Servlets

Introduction to J2EE
Client Server architecture
URL, Port Number, Request, Response
Need for servlets
Servlet fundamentals
Setting up a web project in Eclipse
Configuring and running the web app with servlets
GET and POST request in web application with demo
Servlet lifecycle
Servlets Continued
Session tracking and filter
Forward and include Servlet request dispatchers

Java Server Pages (JSP)

Fundamentals of Java Server Page
Writing a code using JSP
The architecture of JSP
JSP Continued
JSP elements: Scriptlets, expressions, declaration
JSP standard actions
JSP directives
Introduction to JavaBeans
ServletConfig and ServletContext
Servlet Chaining
Cookies Management
Session Management

Hibernate

Introduction to Hibernate
Introduction to ORM
ORM features
Hibernate as an ORM framework
Hibernate features
Setting up a project with Hibernate framework
Basic APIs needed to do CRUD operations with Hibernate
Hibernate Architecture

POJO (Plain Old Java Object)

POJO (Plain Old Java Object)
Persistent Objects
Lifecycle of Persistent Object

Spring

Introduction to Spring
Spring Fundamentals
Advanced Spring

Got a question for us? Please mention it in the comments section and we will get back to you.

347