In this post, we will show you how to configure a Spring Batch job to read data from XML and write into mongo database.

Project structure

This is a directory structure of the standard gradle project.

spring batch xml to mongo example project structure

Project dependencies

task wrapper(type: Wrapper) {
 gradleVersion = '3.2.1'
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
sourceCompatibility = 1.8
repositories {
 mavenLocal()
 mavenCentral()
}
dependencies {
 compile 'org.springframework:spring-oxm:4.3.7.RELEASE'
 compile 'org.springframework.data:spring-data-mongodb:1.9.8.RELEASE'
 compileOnly('org.projectlombok:lombok:1.16.12')
 compile('org.springframework.boot:spring-boot-starter-batch:1.5.2.RELEASE')
 testCompile('org.springframework.boot:spring-boot-starter-test:1.5.2.RELEASE')
}
buildscript {
 repositories {
 mavenLocal()
 jcenter()
 }
 dependencies {
 classpath "org.springframework.boot:spring-boot-gradle-plugin:1.5.2.RELEASE"
 }
}

application.properties file

spring.data.mongodb.host=127.0.0.1
spring.data.mongodb.port=27017
spring.data.mongodb.database=springbatch

Spring Batch Jobs

This is the XML file in the resource folder.

<?xml version="1.0" encoding="UTF-8" ?>
<report>
 <record id="1">
 <date>03/28/2017</date>
 <impression>139,237</impression>
 <clicks>50</clicks>
 <earning>220.90</earning>
 </record>
 <record id="2">
 <date>03/29/2017</date>
 <impression>339,100</impression>
 <clicks>60</clicks>
 <earning>320.88</earning>
 </record>
 <record id="3">
 <date>03/30/2017</date>
 <impression>431,436</impression>
 <clicks>86</clicks>
 <earning>270.80</earning>
 </record>
</report>

(追記) (追記ここまで)

Create a job which will read from xml file using Report object and write into mongo database.

package com.walking.techie.xmltomongo.jobs;
import com.walking.techie.xmltomongo.converter.ReportConverter;
import com.walking.techie.xmltomongo.model.Report;
import java.util.HashMap;
import java.util.Map;
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.data.MongoItemWriter;
import org.springframework.batch.item.xml.StaxEventItemReader;
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;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.oxm.xstream.XStreamMarshaller;
@Configuration
@EnableBatchProcessing
public class XmlTOMongo {
 @Autowired
 private JobBuilderFactory jobBuilderFactory;
 @Autowired
 private StepBuilderFactory stepBuilderFactory;
 @Autowired
 private ReportConverter reportConverter;
 @Autowired
 private MongoTemplate mongoTemplate;
 @Bean
 public Job reportJob() {
 return jobBuilderFactory.get("reportJob").incrementer(new RunIdIncrementer()).flow(step1())
 .end().build();
 }
 @Bean
 public Step step1() {
 return stepBuilderFactory.get("step1").<Report, Report>chunk(10).reader(reader())
 .writer(writer()).build();
 }
 @Bean
 public StaxEventItemReader<Report> reader() {
 StaxEventItemReader<Report> reader = new StaxEventItemReader<>();
 reader.setResource(new ClassPathResource("report.xml"));
 reader.setFragmentRootElementName("record");
 reader.setUnmarshaller(unmarshaller());
 return reader;
 }
 @Bean
 public XStreamMarshaller unmarshaller() {
 XStreamMarshaller unmarshal = new XStreamMarshaller();
 Map<String, Class> aliases = new HashMap<String, Class>();
 aliases.put("record", Report.class);
 unmarshal.setAliases(aliases);
 unmarshal.setConverters(reportConverter);
 return unmarshal;
 }
 @Bean
 public MongoItemWriter<Report> writer() {
 MongoItemWriter<Report> writer = new MongoItemWriter<>();
 writer.setTemplate(mongoTemplate);
 writer.setCollection("report");
 return writer;
 }
}

This is the model java class.

package com.walking.techie.xmltomongo.model;
import java.math.BigDecimal;
import java.util.Date;
import lombok.Data;
@Data
public class Report {
 private int id;
 private Date date;
 private long impression;
 private int clicks;
 private BigDecimal earning;
}

(追記) (追記ここまで)

To map XML value to “complex” data type like Date and BigDecimal, you need to attach a custom converter to convert and map the value manually.

package com.walking.techie.xmltomongo.converter;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.walking.techie.xmltomongo.model.Report;
import java.math.BigDecimal;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import org.springframework.stereotype.Component;
@Component
public class ReportConverter implements Converter {
 @Override
 public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) {
 }
 @Override
 public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
 Report report = new Report();
 report.setId(Integer.valueOf(reader.getAttribute("id")));
 reader.moveDown();// move down
 Date date = null;
 try {
 date = new SimpleDateFormat("MM/dd/yyyy").parse(reader.getValue());
 } catch (ParseException e) {
 e.printStackTrace();
 }
 report.setDate(date);
 reader.moveUp();
 reader.moveDown();//get impression
 String impression = reader.getValue();
 NumberFormat format = NumberFormat.getInstance(Locale.US);
 Number number = 0;
 try {
 number = format.parse(impression);
 } catch (ParseException e) {
 e.printStackTrace();
 }
 report.setImpression(number.longValue());
 reader.moveUp();
 reader.moveDown();//get click
 report.setClicks(Integer.valueOf(reader.getValue()));
 reader.moveUp();
 reader.moveDown();
 report.setEarning(new BigDecimal(reader.getValue()));
 reader.moveUp();
 return report;
 }
 @Override
 public boolean canConvert(Class type) {
 return type.equals(Report.class);
 }
}

Run Application

package com.walking.techie;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class Application {
 public static void main(String[] args) {
 SpringApplication.run(Application.class, args);
 }
}

Output

You can verify output of this program in your mongo DB report collection, There you will see three document.

output on console

2017年03月29日 12:31:22.836 INFO 36317 --- [ main] o.s.b.c.l.support.SimpleJobLauncher : Job: [FlowJob: [name=reportJob]] launched with the following parameters: [{run.id=1}]
2017年03月29日 12:31:22.857 INFO 36317 --- [ main] o.s.batch.core.job.SimpleStepHandler : Executing step: [step1]
2017年03月29日 12:31:22.943 INFO 36317 --- [ main] org.mongodb.driver.connection : Opened connection [connectionId{localValue:2, serverValue:390}] to 127.0.0.1:27017
2017年03月29日 12:31:22.968 INFO 36317 --- [ main] o.s.b.c.l.support.SimpleJobLauncher : Job: [FlowJob: [name=reportJob]] completed with the following parameters: [{run.id=1}] and the following status: [COMPLETED]

Note : This code has been compiled and run on mac notebook and intellij IDEA.