Spring Batch MySQL到文件

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2023-03-14

在本章中，我们将创建一个使用MySQL Reader和Flatfile Writer(.txt)的Spring Batch应用程序。

Reader - 在应用程序中使用的Reader是JdbcCursorItemReader，用于从MySQL数据库读取数据。

假设在MySQL数据库中创建了一个表，如下所示。

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

假设已经在其中插入了以下记录。

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 - 在应用程序中使用的Writer是FlatFileItemWriter，用于将数据写入flatfile(.txt)。

Processor - 在应用程序中使用的处理器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Spring Batch应用程序的配置文件。在这个文件中，我们将定义Job和Steps。除此之外，还为ItemReader，ItemProcessor和ItemWriter定义了bean。 (在这里，将它们与相应的类相关联，并传递所需属性的值来配置它们。)

<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 = "context.xml" />  
   <bean id = "tutorial" class = "Tutorial" scope = "prototype" /> 
   <bean id = "itemProcessor" class = "CustomItemProcessor" />  

   <batch:job id = "helloWorldJob"> 
      <batch:step id = "step1"> 
         <batch:tasklet> 
            <batch:chunk reader = "mysqlItemReader" 
               writer = "flatFileItemWriter" processor = "itemProcessor" 
               commit-interval = "10"> 
            </batch:chunk> 
         </batch:tasklet> 
      </batch:step> 
   </batch:job> 

   <bean id = "mysqlItemReader" 
      class = "org.springframework.batch.item.database.JdbcCursorItemReader" > 
      <property name = "dataSource" ref = "dataSource" /> 
      <property name = "sql" value = "select * from details.tutorialsdata" /> 
      <property name = "rowMapper">  
         <bean class = "TutorialRowMapper" /> 
      </property> 
   </bean>

   <bean id = "flatFileItemWriter" 
      class = " org.springframework.batch.item.file.FlatFileItemWriter">      
      <property name = "resource" value = "file:target/outputfiles/employee_output.txt"/> 
      <property name = "lineAggregator"> 
         <bean class = " org.springframework.batch.item.file.transform.PassThroughLineAggregator"/> 
      </property> 
   </bean> 
</beans>

context.xml

以下是Spring Batch应用程序的context.xml。在这个文件中，我们将定义bean，如作业存储库，作业启动器和事务管理器。

<beans xmlns = "http://www.springframework.org/schema/beans" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" 
   xmlns:jdbc = "http://www.springframework.org/schema/jdbc" 
   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 = "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 = "123456" /> 
   </bean> 

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

以下是处理器类。在这个类中，我们在应用程序中编写处理代码。在这里，我们正在打印每条记录的内容。

import org.springframework.batch.item.ItemProcessor;  

// Implementing the ItemProcessor interface 
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。

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_title(rs.getString("tutorial_title")); 
      tutorial.setTutorial_author(rs.getString("tutorial_author")); 
      tutorial.setSubmission_date(rs.getString("submission_date"));  
      return tutorial; 
   } 
}

Tutorial.java

以下是Tutorial类。它是一个简单的带有setter和getter方法的Java类。在这个类中，我们使用注释来将这个类的方法与XML文件的标签关联起来。

public class Tutorial { 
   private int tutorial_id; 
   private String tutorial_title; 
   private String tutorial_author; 
   private String submission_date; 

   public int getTutorial_id() { 
      return tutorial_id; 
   }  

   public void setTutorial_id(int tutorial_id) { 
      this.tutorial_id = tutorial_id; 
   }

   public String getTutorial_title() { 
      return tutorial_title; 
   }   

   public void setTutorial_title(String tutorial_title) { 
      this.tutorial_title = tutorial_title; 
   }  

   public String getTutorial_author() { 
      return tutorial_author; 
   }  

   public void setTutorial_author(String tutorial_author) { 
      this.tutorial_author = tutorial_author; 
   }  

   public String getSubmission_date() { 
      return submission_date; 
   }  
   public void setSubmission_date(String submission_date) { 
      this.submission_date = submission_date; 
   }  

   @Override 
   public String toString() { 
      return " [id=" + tutorial_id + ", title=" + 
      tutorial_title                      + ", 
      author=" + tutorial_author + ", date=" + 
      submission_date + "]"; 
   } 
}

App.java

以下是启动批处理过程的代码。在这个类中，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  =  { "context.xml", "jobcontext.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()); 
   } 
}

在执行这个应用程序时，它将产生以下输出。

May 09, 2017 5:44:48 PM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 
INFO: Refreshing org.springframework.context.support.ClassPathXml
ApplicationContext@3d646c37: startup date [Tue May 
09 17:44:48 IST 2017]; root of context hierarchy 
May 09, 2017 5:44:48 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions  
May 09, 2017 5:44:56 PM org.springframework.batch.core.launch.support.SimpleJobLauncher run 
INFO: Job: [FlowJob: [name=helloWorldJob]] launched 
with the following parameters: [{}] 
May 09, 2017 5:44:56 PM org.springframework.batch.core.job.SimpleStepHandler handleStep 
INFO: Executing step: [step1] 
Processing...Report [id=101, title=Learn Java, author=Sanjay, date=06-05-2007] 
Processing...Report [id=102, title=Learn MySQL, author=Abdul S, date=19-04-2007] 
Processing...Report [id=103, title=Learn JavaFX, author=Krishna Kasyap, date=0607-2017] 
May 09, 2017 5:44:57 PM org.springframework.batch.core.launch.support.SimpleJobLauncher run 
INFO: Job: [FlowJob: [name=helloWorldJob]] completed with the following parameters: 
[{}] and the following status: [COMPLETED] 
Hello 
Exit Status : COMPLETED