Basic Application

本章介绍基本的Spring Batch应用程序。 它将简单地执行一个tasklet来显示一条消息。

我们的Spring Batch应用程序包含以下文件 -

• Configuration file - 这是一个XML文件，我们在其中定义作业和作业的步骤。 （如果应用程序也涉及读者和编写者，那么读者和编写者的配置也包含在此文件中。）

• Context.xml - 在此文件中，我们将定义诸如作业存储库，作业启动程序和事务管理器之类的bean。

• Tasklet class - 在这个类中，我们将编写处理代码作业（在这种情况下，它显示一个简单的消息）

• Launcher class - 在此类中，我们将通过运行Job启动器来启动Batch Application。

jobConfig.xml

以下是我们的示例Spring Batch应用程序的配置文件。

<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="context.xml" />      
   <!-- Defining a bean --> 
   <bean id = "tasklet" class = "a_sample.MyTasklet" />  
   <!-- Defining a job--> 
   <batch:job id = "helloWorldJob">  
      <!-- Defining a Step --> 
      <batch:step id = "step1"> 
         <tasklet ref = "tasklet"/>   
      </batch:step>    
   </batch:job>  
</beans> 

Context.xml

以下是我们的Spring Batch应用程序的context.xml 。

<beans xmlns = "http://www.springframework.org/schema/beans" 
   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">  
   <bean id = "jobRepository"   
     > 
      <property name = "transactionManager" ref = "transactionManager" /> 
   </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> 
</beans> 

Tasklet.java

以下是Tasklet类，它显示一条简单的消息。

import org.springframework.batch.core.StepContribution; 
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;  
public class MyTasklet implements Tasklet { 
   @Override 
   public RepeatStatus execute(StepContribution arg0, ChunkContext arg1) throws Exception {  
      System.out.println("Hello This is a sample example of spring batch"); 
      return RepeatStatus.FINISHED; 
   } 
} 

App.java

以下是启动批处理过程的代码。

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 { 
      // System.out.println("hello"); 
      String[] springConfig  =  {"a_sample/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()); 
   }    
}

执行时，上面的SpringBatch程序将产生以下输出 -

Apr 24, 2017 4:40:54 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh 
INFO:Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@2ef1e4fa: startup date [Mon Apr 24 16:40:54 IST 2017]; root of context hierarchy 
Apr 24, 2017 4:40:54 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO: Loading XML bean definitions  
Apr 24, 2017 4:40:54 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions  
INFO: Loading XML bean definitions 
Apr 24, 2017 4:40:54 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons 
Apr 24, 2017 4:40:55 PM org.springframework.batch.core.launch.support.SimpleJobLauncher afterPropertiesSet 
INFO: No TaskExecutor has been set, defaulting to synchronous executor. 
Apr 24, 2017 4:40:55 PM org.springframework.batch.core.launch.support.SimpleJobLauncher$1 run 
INFO: Job: [FlowJob: [name=helloWorldJob]] launched with the following parameters: [{}] 
Apr 24, 2017 4:40:55 PM org.springframework.batch.core.job.SimpleStepHandler handleStep INFO: Executing step: [step1] 
Hello This is a sample example of spring batch 
Apr 24, 2017 4:40:55 PM org.springframework.batch.core.launch.support.SimpleJobLauncher$1 run 
INFO: Job: [FlowJob: [name=helloWorldJob]] completed with the following parameters: [{}] and the following status: [COMPLETED] 
Exit Status : COMPLETED