Spring Batch 简明教程

Spring Batch - MySQL to XML

在本章中，我们将创建一个 Spring Batch 应用程序，它使用 MySQL reader 和 XML Writer。

In this chapter, we will create a Spring Batch application which uses a MySQL reader and an XML Writer.

Reader − 应用程序中使用的 reader 是 JdbcCursorItemReader ，用来从 MySQL 数据库中读取数据。

Reader − The reader we are using in the application is JdbcCursorItemReader to read data from MySQL database.

假设我们在 MySQL 数据库中创建了一个表，如下所示 −

Assume we have created a table in the MySQL database as shown below −

CREATE TABLE details.xml_mysql(
   person_id int(10) NOT NULL,
   sales VARCHAR(20),
   qty int(3),
   staffName VARCHAR(20),
   date VARCHAR(20)
);

假设我们在其中插入了以下记录。

Assume we have inserted the following records in to it.

mysql> select * from tutorialsdata;
+-------------+-----------------+----------------+-----------------+
| tutorial_id | tutorial_author | tutorial_title | submission_date |
+-------------+-----------------+----------------+-----------------+
|         101 | Sanjay          | Learn Java     | 06-05-2007      |
|         102 | Abdul S         | Learn MySQL    | 19-04-2007      |
|         103 | Krishna Kasyap  | Learn JavaFX   | 06-07-2017      |
+-------------+-----------------+----------------+-----------------+
3 rows in set (0.00 sec)

Writer − 应用程序中使用的 Writer 是 StaxEventItemWriter ，用来将数据写入 XML 文件。

Writer − The Writer we are using in the application is StaxEventItemWriter to write the data to the XML file.

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。

Processor − The Processor we are using in the application is a custom processor which just prints the records read from the CSV file.

jobConfig.xml

以下是样例 Spring Batch 应用程序的配置文件。在该文件中，我们将定义 Job 和 Step。此外，我们还定义了 ItemReader、ItemProcessor 和 ItemWriter 的 bean。（在这里，我们将它们与其各自的类合并，并传递所需的属性值来配置它们。）

Following is the configuration file of our sample Spring Batch application. In this file, we will define the Job and the Steps. In addition to these, we also define the beans for ItemReader, ItemProcessor, and ItemWriter. (Here, we associate them with their respective classes and pass the values for the required properties to configure them.)

<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"
   xmlns:util = "http://www.springframework.org/schema/util"
   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 = "dbItemReader"
               writer = "mysqlItemWriter" processor = "itemProcessor" commit-interval = "10">
            </batch:chunk>
         </batch:tasklet>
      </batch:step>
   </batch:job>

   <bean id = "dbItemReader"
      class = "org.springframework.batch.item.database.JdbcCursorItemReader" scope = "step">
      <property name = "dataSource" ref = "dataSource" />
      <property name = "sql" value = "select * from tutorials_data" />
      <property name = "rowMapper">
         <bean class = "TutorialRowMapper" />
      </property>
   </bean>
   <bean id = "mysqlItemWriter"
      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 = "Tutorial" />
   </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。

Following is the context.xml of our Spring Batch application. In this file, we will define the beans like job repository, job launcher, and transaction manager.

<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.ResourcelessTransactionMana ger" />
   <bean id = "jobLauncher"
      class = "org.springframework.batch.core.launch.support.SimpleJobLauncher">
      <property name = "jobRepository" ref = "jobRepository" />
   </bean>

   <!-- connect to MySQL database -->
   <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。

Following is the Processor class. In this class, we write the code of processing in the application. Here, we are printing the contents of each record.

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;
   }
}

TutorialRowMapper.java

以下是 TutorialRowMapper 类，它将数据设置为 Tutorial 类。

Following is the TutorialRowMapper class which sets the data to the Tutorial class.

import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;

public class TutorialRowMapper implements RowMapper<Tutorial> {

   @Override
   public Tutorial mapRow(ResultSet rs, int rowNum) throws SQLException {

      Tutorial tutorial = new Tutorial();
      tutorial.setTutorial_id(rs.getInt("tutorial_id"));
      tutorial.setTutorial_author(rs.getString("tutorial_author"));
      tutorial.setTutorial_title(rs.getString("tutorial_title"));
      tutorial.setSubmission_date(rs.getString("submission_date"));
      return tutorial;
   }
}

Tutorial.java

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。

Following is the Tutorial class. It is a simple Java class with setter and getter methods. In this class, we are using annotations to associate the methods of this class with the tags of the XML file.

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

@XmlRootElement(name = "details")
public class Tutorial {

   int tutorial_id;
   String tutorial_author;
   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;
   }

   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。在该类中，我们将通过运行 JobLauncher 来启动 Batch 应用程序。

Following is the code which launces the batch process. In this class, we will launch the Batch Application by running the 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());
   }
}

执行此应用程序后，它将生成以下输出。

On executing this application, it will produce the following output.

May 08, 2017 11:32:06 AM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3d646c37:
startup date [Mon May 08 11:32:06 IST 2017]; root of context hierarchy
May 08, 2017 11:32:06 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [jobs/job_hello_world.xml]
May 08, 2017 11:32:07 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
May 08, 2017 11:32:14 AM org.springframework.batch.core.job.SimpleStepHandler handleStep
INFO: Executing step: [step1]
Processing... [Tutorial Id=101, Tutorial Author=Sanjay,
Tutorial Title=Learn Java, Submission Date=06-05-2007]
Processing... [Tutorial Id=102, Tutorial Author=Abdul S,
Tutorial Title=Learn MySQL, Submission Date=19-04-2007]
Processing... [Tutorial Id=103, Tutorial Author=Krishna Kasyap,
Tutorial Title=Learn JavaFX, Submission Date=06-07-2017]
May 08, 2017 11:32:14 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。

This will generate an XML file with the following contents.

<?xml version = "1.0" encoding = "UTF-8"?>
<Tutorial>
   <details tutorial_id = "101">
      <submission_date>06-05-2007</submission_date>
      <tutorial_author>Sanjay</tutorial_author>
      <tutorial_title>Learn Java</tutorial_title>
   </details>

   <details tutorial_id = "102">
      <submission_date>19-04-2007</submission_date>
      <tutorial_author>Abdul S</tutorial_author>
      <tutorial_title>Learn MySQL</tutorial_title>
   </details>

   <details tutorial_id = "103">
      <submission_date>06-07-2017</submission_date>
      <tutorial_author>Krishna Kasyap</tutorial_author>
      <tutorial_title>Learn JavaFX</tutorial_title>
   </details>
</Tutorial>