MySQL to XML Spring Boot Batch Example

MySQL to XML Spring Boot Batch | Previously we have seen Spring Boot Batch examples of CSV to MySQL, CSV to MongoDB, MySQL to CSV, and MongoDB to CSV. Now let us see MongoDB to CSV file through Spring Boot Batch. Also see:- Spring Boot Batch API Introduction

We will need JAXB (Java Architecture for XML Binding) for this. It provides two operations:-

• Marshaling:- Converting Java Object to XML Format.
• Unmarshalling:- Converting XML to Java Object Format.

To do marshalling and unmarshalling we can use Spring OXM (Object XML Mapping) dependency which internally uses JAXB.

Create a Spring starter project SpringBoot2MySQLToXML with the following dependencies:- Batch API, Lombok, MySQL, Spring Data JPA, and Spring Web. Also add the below dependencies:-

Spring OXM

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-oxm</artifactId>
</dependency>

JAXB-API

<dependency>
    <groupId>javax.xml.bind</groupId>
    <artifactId>jaxb-api</artifactId>
</dependency>

XML.BIND-API

<dependency>
    <groupId>jakarta.xml.bind</groupId>
    <artifactId>jakarta.xml.bind-api</artifactId>
</dependency>

JAXB-RUNTIME

<dependency>
    <groupId>org.glassfish.jaxb</groupId>
    <artifactId>jaxb-runtime</artifactId>
</dependency>

In the model class, we must add @XmlRootElement then its object will be eligible for marshaling/unmarshaling.

In application.properties file:-

# DB details
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root

# JPA info
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.format_sql=true

# disable job run at startup
spring.batch.job.enabled=false 
spring.batch.jdbc.initialize-schema=always

Model class:-

package com.knowprogram.demo.model;

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import jakarta.xml.bind.annotation.XmlRootElement;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name = "prod")
@XmlRootElement(name="product")
public class Product {
    @Id
    @Column(name = "pid")
    private Integer prodId;
    
    @Column(name = "pname")
    private String prodCode;
    
    @Column(name = "pcost")
    private Double prodCost;
    
    @Column(name = "ptax")
    private Double prodTax;
    
    @Column(name = "pdiscount")
    private Double prodDiscount;
}

Repository:-

package com.knowprogram.demo.repository;

import org.springframework.data.jpa.repository.JpaRepository;

import com.knowprogram.demo.model.Product;

public interface ProductRepository extends JpaRepository<Product, Integer> {

}

BatchConfig:-

package com.knowprogram.demo.config;

import java.util.Collections;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobExecutionListener;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.job.builder.JobBuilder;
import org.springframework.batch.core.repository.JobRepository;
import org.springframework.batch.core.step.builder.StepBuilder;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.data.RepositoryItemReader;
import org.springframework.batch.item.xml.StaxEventItemWriter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.task.SimpleAsyncTaskExecutor;
import org.springframework.data.domain.Sort;
import org.springframework.oxm.jaxb.Jaxb2Marshaller;
import org.springframework.transaction.PlatformTransactionManager;

import com.knowprogram.demo.model.Product;
import com.knowprogram.demo.repository.ProductRepository;

@Configuration
public class BatchConfig {

    @Autowired
    private ProductRepository productRepository;

    @Bean
    ItemReader<Product> reader() {
        RepositoryItemReader<Product> reader = new RepositoryItemReader<>();
        reader.setRepository(productRepository);
        reader.setMethodName("findAll");
        reader.setPageSize(10);
        reader.setSort(Collections.singletonMap("prodId", Sort.Direction.ASC));
        return reader;
    }

    @Bean
    ItemProcessor<Product, Product> processor() {
        return item -> item;
    }
    
    @Bean
    Jaxb2Marshaller marshaller() {
        Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
        marshaller.setClassesToBeBound(Product.class);
        return marshaller;
    }

    @Bean
    ItemWriter<Product> writer() {
        // Stax = Streaming API for XML (JAXB)
        StaxEventItemWriter<Product> writer = new StaxEventItemWriter<>();
        // XML file location
        writer.setResource(new FileSystemResource("V:/myouts/product_data.xml"));
        writer.setMarshaller(marshaller());
        writer.setRootTagName("products");
        return writer;
    }

    @Bean
    Step step(JobRepository repository, PlatformTransactionManager transactionManager) {
        return new StepBuilder("csv-step", repository)
                .<Product, Product>chunk(10, transactionManager)
                .reader(reader())
                .processor(processor())
                .writer(writer())
                .taskExecutor(new SimpleAsyncTaskExecutor() {
                    private static final long serialVersionUID = 1L;

                    {
                        setConcurrencyLimit(10);
                    }
                })
                .build();
    }

    @Bean
    JobExecutionListener listener() {
        return new JobExecutionListener() {
            @Override
            public void beforeJob(JobExecution jobExecution) {
                System.out.println("MyJobListener.beforeJob()");
            }

            @Override
            public void afterJob(JobExecution jobExecution) {
                System.out.println("MyJobListener.afterJob()");
            }
        };
    }

    @Bean(name = "csvJob")
    Job job(JobRepository jobRepository, PlatformTransactionManager transactionManager) {
        return new JobBuilder("csv-job", jobRepository)
                .listener(listener())
                .flow(step(jobRepository, transactionManager))
                .end()
                .build();
    }
}

Controller class:-

@RestController
package com.knowprogram.demo.controller;

public class ProductBatchController {

    @Autowired
    private JobLauncher jobLauncher;

    @Autowired
    private Job job;

    @GetMapping("/startBatch")
    public String startBatch() throws JobExecutionAlreadyRunningException, 
        JobRestartException,
        JobInstanceAlreadyCompleteException, 
        JobParametersInvalidException {
        JobParameters params = new JobParametersBuilder()
             .addLong("time", System.currentTimeMillis())
             .toJobParameters();

        JobExecution run = jobLauncher.run(job, params);
        return run.getStatus().toString();
    }

}

The generated XML file contains:-

<?xml version="1.0" encoding="UTF-8"?>
<products>
    <product>
        <prodCode>BOOK</prodCode>>
        <prodCost>500.0</prodCost>
        <prodDiscount>40.0</prodDiscount>
        <prodId>11</prodId>
        <prodTax>60.0</prodTax>
    </product>>
    <product>
        <prodCode>PEN</prodCode>
        <prodCost200.0
        </prodCost>
        <prodDiscount>16.0</prodDiscount>
        <prodId>10</prodId>
        <prodTax>24.0</prodTax>
    </product>
    <product>
        <prodCode>MOUSE</prodCode>
        <prodCost>300.0</prodCost>
        <prodDiscount>24.0</prodDiscount>
        <prodId>14</prodId>
        <prodTax>36.0</prodTax>
    </product>
    <product>
        <prodCode>BOTTLE</prodCode>
        <prodCost>600.0</prodCost>
        <prodDiscount>48.0</prodDiscount>
        <prodId>12</prodId>
        <prodTax>72.0</prodTax>
    </product>
    <product>
        <prodCode>KEYBOAD</prodCode>
        <prodCost>900.0</prodCost>
        <prodDiscount>72.0</prodDiscount>
        <prodId>15</prodId>
        <prodTax>108.0</prodTax>
    </product>
    <product>
        <prodCode>MOBILE</prodCode>
        <prodCost>1500.0</prodCost>
        <prodDiscount>120.0</prodDiscount>
        <prodId>13</prodId>
        <prodTax>180.0</prodTax>
    </product>
    <product>
        <prodCode>BAG</prodCode>
        <prodCost>600.0</prodCost>
        <prodDiscount>48.0</prodDiscount>
        <prodId>16</prodId>
        <prodTax>72.0</prodTax>
    </product>
</products>

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