Spring Batch - CSV para XML

Neste capítulo, criaremos um aplicativo Spring Batch simples que usa um CSV Reader e um XML Writer.

Reader - o reader que estamos usando no aplicativo é FlatFileItemReader para ler dados dos arquivos CSV.

A seguir está o arquivo CSV de entrada que estamos usando neste aplicativo. Este documento contém registros de dados que especificam detalhes como id do tutorial, autor do tutorial, título do tutorial, data de envio, ícone do tutorial e descrição do tutorial.

1001, "Sanjay", "Learn Java", 06/05/2007 
1002, "Abdul S", "Learn MySQL", 19/04/2007 
1003, "Krishna Kasyap", "Learn JavaFX", 06/07/2017

Writer - O escritor que estamos usando no aplicativo é StaxEventItemWriter para gravar os dados no arquivo XML.

Processor - O processador que estamos usando no aplicativo é um processador personalizado que apenas imprime os registros lidos do arquivo CSV.

jobConfig.xml

A seguir está o arquivo de configuração de nosso aplicativo Spring Batch de amostra. Neste arquivo definiremos o Job e as etapas. Além disso, também definimos os beans para ItemReader, ItemProcessor e ItemWriter. (Aqui, nós os associamos às respectivas classes e passamos os valores para as propriedades necessárias para configurá-los.)

<beans xmlns = " http://www.springframework.org/schema/beans" 
   xmlns:batch = "http://www.springframework.org/schema/batch" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" 
   xsi:schemaLocation = "http://www.springframework.org/schema/batch 
      http://www.springframework.org/schema/batch/spring-batch-2.2.xsd 
      http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">  
   
   <import resource = "../jobs/context.xml" />  
   
   <bean id = "report" class = "Report" scope = "prototype" /> 
   <bean id = "itemProcessor" class = "CustomItemProcessor" />  
   
   <batch:job id = "helloWorldJob"> 
   
      <batch:step id = "step1"> 
   
         <batch:tasklet> 
            <batch:chunk reader = "cvsFileItemReader" writer = "xmlItemWriter" 
               processor = "itemProcessor" commit-interval = "10"> 
            </batch:chunk> 
         </batch:tasklet> 
      </batch:step> 
   </batch:job>  
 
   <bean id = "cvsFileItemReader" 
      class = "org.springframework.batch.item.file.FlatFileItemReader">  
      <property name = "resource" value = "classpath:resources/report.csv" /> 
      <property name = "lineMapper"> 
         <bean 
            class = "org.springframework.batch.item.file.mapping.DefaultLineMapper"> 
            <property name = "lineTokenizer"> 
               <bean    
                  class = "org.springframework.batch.item.file.transform.DelimitedLineTokenizer"> 
                  <property name = "names" value = "tutorial_id, 
                     tutorial_author, Tutorial_title, submission_date" /> 
               </bean> 
            </property> 
      
            <property name = "fieldSetMapper"> 
               <bean class = "ReportFieldSetMapper" /> 
            </property> 
         </bean> 
      </property> 
   </bean>  
   
   <bean id = "xmlItemWriter" 
      class = "org.springframework.batch.item.xml.StaxEventItemWriter"> 
      <property name = "resource" value = "file:xml/outputs/tutorials.xml" /> 
      <property name = "marshaller" ref = "reportMarshaller" /> 
      <property name = "rootTagName" value = "tutorials" /> 
   </bean>  
 
   <bean id = "reportMarshaller" 
      class = "org.springframework.oxm.jaxb.Jaxb2Marshaller">
      <property name = "classesToBeBound"> 
         <list> 
            <value>Tutorial</value> 
         </list> 
      </property> 
   </bean> 
</beans>

Context.xml

A seguir está o context.xmlde nosso aplicativo Spring Batch. Neste arquivo, definiremos os beans como repositório de trabalhos, lançador de trabalhos e gerenciador de transações.

<beans xmlns = "http://www.springframework.org/schema/beans" 
   xmlns:jdbc = "http://www.springframework.org/schema/jdbc" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" 
   xsi:schemaLocation = "http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
      http://www.springframework.org/schema/jdbc 
      http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd">  
   <!-- stored job-meta in database --> 
   <bean id = "jobRepository" 
      class = "org.springframework.batch.core.repository.support.JobRepositoryFactoryBean"> 
      <property name = "dataSource" ref = "dataSource" /> 
      <property name = "transactionManager" ref = "transactionManager" /> 
      <property name = "databaseType" value = "mysql" /> 
   </bean>  
 
   <bean id = "transactionManager" 
      class = "org.springframework.batch.support.transaction.ResourcelessTransactionManager" />  
   <bean id = "jobLauncher" 
      class = "org.springframework.batch.core.launch.support.SimpleJobLauncher"> 
      <property name = "jobRepository" ref = "jobRepository" /> 
   </bean>  
   
   <bean id = "dataSource" class = "org.springframework.jdbc.datasource.DriverManagerDataSource"> 
      <property name = "driverClassName" value = "com.mysql.jdbc.Driver" /> 
      <property name = "url" value = "jdbc:mysql://localhost:3306/details" />
      <property name = "username" value = "myuser" /> 
      <property name = "password" value = "password" /> 
   </bean> 
  
   <!-- create job-meta tables automatically --> 
   <jdbc:initialize-database data-source = "dataSource">   
      <jdbc:script location = "org/springframework/batch/core/schema-drop-mysql.sql" /> 
      <jdbc:script location = "org/springframework/batch/core/schema-mysql.sql" /> 
   </jdbc:initialize-database> 
</beans>

CustomItemProcessor.java

A seguir está a classe Processor. Nesta aula, escrevemos o código de processamento no aplicativo. Aqui, estamos imprimindo o conteúdo de cada registro.

import org.springframework.batch.item.ItemProcessor;  

public class CustomItemProcessor implements ItemProcessor<Tutorial, Tutorial> {  
   
   @Override 
   public Tutorial process(Tutorial item) throws Exception {  
      System.out.println("Processing..." + item); 
      return item; 
   } 
}

TutorialFieldSetMapper.java

A seguir está a classe TutorialFieldSetMapper que define os dados para a classe Tutorial.

import org.springframework.batch.item.file.mapping.FieldSetMapper; 
import org.springframework.batch.item.file.transform.FieldSet; 
import org.springframework.validation.BindException;  

public class TutorialFieldSetMapper implements FieldSetMapper<Tutorial> {  

   @Override 
   public Tutorial mapFieldSet(FieldSet fieldSet) throws BindException {  
      
      //Instantiating the report object  
      Tutorial tutorial = new Tutorial(); 
       
      //Setting the fields  
      tutorial.setTutorial_id(fieldSet.readInt(0)); 
      tutorial.setTutorial_author(fieldSet.readString(1)); 
      tutorial.setTutorial_title(fieldSet.readString(2)); 
      tutorial.setSubmission_date(fieldSet.readString(3)); 
       
      return tutorial; 
   } 
}

Classe Tutorial.java

A seguir está o Tutorialclasse. É uma classe Java simples comsetter e gettermétodos. Nesta classe, estamos usando anotações para associar os métodos desta classe às tags do arquivo XML.

import javax.xml.bind.annotation.XmlAttribute; 
import javax.xml.bind.annotation.XmlElement; 
import javax.xml.bind.annotation.XmlRootElement;  

@XmlRootElement(name = "tutorial") 
public class Tutorial {  
   private int tutorial_id; 
   private String tutorial_author; 
   private String tutorial_title;
   private String submission_date;  
 
   @XmlAttribute(name = "tutorial_id") 
   public int getTutorial_id() { 
      return tutorial_id; 
   }  
 
   public void setTutorial_id(int tutorial_id) { 
      this.tutorial_id = tutorial_id; 
   }  
 
   @XmlElement(name = "tutorial_author") 
   public String getTutorial_author() { 
      return tutorial_author; 
   }  
   public void setTutorial_author(String tutorial_author) { 
      this.tutorial_author = tutorial_author; 
   }  
      
   @XmlElement(name = "tutorial_title") 
   public String getTutorial_title() { 
      return tutorial_title; 
   }  
   
   public void setTutorial_title(String tutorial_title) { 
      this.tutorial_title = tutorial_title; 
   }  
   
   @XmlElement(name = "submission_date") 
   public String getSubmission_date() { 
      return submission_date; 
   }  
   
   public void setSubmission_date(String submission_date) { 
      this.submission_date = submission_date; 
   } 
   
   @Override 
   public String toString() { 
      return "  [Tutorial id=" + tutorial_id + ", 
         Tutorial Author=" + tutorial_author  + ", 
         Tutorial Title=" + tutorial_title + ", 
         Submission Date=" + submission_date + "]"; 
   } 
}

App.java

A seguir está o código que inicia o processo em lote. Nesta aula, iniciaremos o aplicativo em lote executando o JobLauncher.

import org.springframework.batch.core.Job; 
import org.springframework.batch.core.JobExecution; 
import org.springframework.batch.core.JobParameters; 
import org.springframework.batch.core.launch.JobLauncher; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext;  

public class App {  
   public static void main(String[] args) throws Exception { 
     
      String[] springConfig  =  { "jobs/job_hello_world.xml" };  
      
      // Creating the application context object        
      ApplicationContext context = new ClassPathXmlApplicationContext(springConfig);  
      
      // Creating the job launcher 
      JobLauncher jobLauncher = (JobLauncher) context.getBean("jobLauncher"); 
   
      // Creating the job 
      Job job = (Job) context.getBean("helloWorldJob"); 
   
      // Executing the JOB 
      JobExecution execution = jobLauncher.run(job, new JobParameters());
      System.out.println("Exit Status : " + execution.getStatus()); 
   } 
}

Ao executar este aplicativo, ele produzirá a seguinte saída.

May 08, 2017 10:10:12 AM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 
INFO: Refreshing 
org.springframework.context.support.ClassPathXmlApplicationContext@3d646c37: startup date 
[Mon May 08 10:10:12 IST 2017]; root of context hierarchy 
May 08, 2017 10:10:12 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 
May 08, 2017 10:10:15 AM org.springframework.jdbc.datasource.init.ScriptUtils executeSqlScript 
INFO: Executing step: [step1] 
Processing...  [Tutorial id=1001, Tutorial Author=Sanjay, 
Tutorial Title=Learn Java, Submission Date=06/05/2007] 
Processing...  [Tutorial id=1002, Tutorial Author=Abdul S, 
Tutorial Title=Learn MySQL, Submission Date=19/04/2007] 
Processing...  [Tutorial id=1003, Tutorial Author=Krishna Kasyap, 
Tutorial Title=Learn JavaFX, Submission Date=06/07/2017] 
May 08, 2017 10:10:21 AM org.springframework.batch.core.launch.support.SimpleJobLauncher run 
INFO: Job: [FlowJob: [name=helloWorldJob]] completed with the following parameters: 
[{}] and the following status: [COMPLETED] 
Exit Status : COMPLETED

Isso irá gerar um arquivo XML com o seguinte conteúdo.

<?xml version = "1.0" encoding = "UTF-8"?> 
<tutorials> 
   <tutorial tutorial_id = "1001"> 
      <submission_date>06/05/2007</submission_date> 
      <tutorial_author>Sanjay</tutorial_author> 
      <tutorial_title>Learn Java</tutorial_title> 
   </tutorial> 
   
   <tutorial tutorial_id = "1002"> 
      <submission_date>19/04/2007</submission_date> 
      <tutorial_author>Abdul S</tutorial_author> 
      <tutorial_title>Learn MySQL</tutorial_title> 
   </tutorial> 
   
   <tutorial tutorial_id = "1003"> 
      <submission_date>06/07/2017</submission_date>
      <tutorial_author>Krishna Kasyap</tutorial_author> 
      <tutorial_title>Learn JavaFX</tutorial_title> 
   </tutorial> 
</tutorials>