Spring Batch 简明教程

Spring Batch - CSV to XML

在本章，我们将创建一个简单的 Spring Batch 应用程序，此应用程序使用 CSV Reader 和 XML Writer。

Reader − 我们在应用程序中使用的 reader 是 FlatFileItemReader ，用于从 CSV 文件中读取数据。

以下是我们在此应用程序中使用的输入 CSV 文件。此文档保存指定详情记录的数据，例如教程 ID、教程作者、教程标题、提交日期、教程图标和教程描述。

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

Writer − 我们在应用程序中使用的 Writer 是 StaxEventItemWriter ，用于将数据写入 XML 文件。

Processor − 我们在应用程序中使用的 Processor 是一个自定义处理器，它只是打印从 CSV 文件中读取的记录。

jobConfig.xml

以下是我们样例 Spring Batch 应用程序的配置文件。在此文件中，我们将定义任务和步骤。此外，我们还定义 ItemReader、ItemProcessor 和 ItemWriter 的 bean。（在此，我们将其与各自的类相关联，并传递所需属性的值以对其进行配置。）

<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

以下是我们 Spring Batch 应用程序的 context.xml 。在该文件中，我们将定义 Bean，如 Job 存储库、Job 启动器和事务管理器。

<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

以下是 Processor 类。在该类中，我们编写应用程序的处理代码。此处，我们打印每个记录的内容。

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

以下是 TutorialFieldSetMapper 类，此类将数据设置为 Tutorial 类。

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;
   }
}

Tutorial.java class

以下是 Tutorial 类。它是一个简单的 Java 类，具有 setter 和 getter 方法。在该类中，我们使用注解来将该类的这些方法与 XML 文件的这些标记相关联。

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

以下是启动批处理的代码。在此类中，我们将通过运行 JobLauncher 来启动批处理应用程序。

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());
   }
}

执行此应用程序后，它将生成以下输出。

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

这将生成包含以下内容的 XML 文件。

<?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>