📅 最后修改于: 2020-11-11 06:54:55 🧑 作者: Mango
在本章中，我们将创建一个使用MySQL阅读器和Flatfile Writer(.txt)的Spring Batch应用程序。
阅读器-我们正在使用的应用程序，读者可以JdbcCursorItemReader从MySQL数据库中读取数据。
假设我们已经在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)
);
假设我们已将以下记录插入其中。
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-我们在应用程序中使用的Writer是FlatFileItemWriter，用于将数据写入Flatfile (.txt)。
处理器-我们在应用程序中使用的处理器是一个自定义处理器，它仅打印从CSV文件读取的记录。
以下是我们的示例Spring Batch应用程序的配置文件。在此文件中，我们将定义作业和步骤。除了这些，我们还为ItemReader，ItemProcessor和ItemWriter定义了bean。 (在这里，我们将它们与相应的类相关联，并传递所需属性的值以进行配置。)
以下是我们的Spring Batch应用程序的context.xml 。在此文件中，我们将定义诸如作业存储库，作业启动器和事务管理器之类的Bean。
以下是Processor类。在此类中，我们在应用程序中编写处理代码。在这里，我们正在打印每个记录的内容。
import org.springframework.batch.item.ItemProcessor;
// Implementing the ItemProcessor interface
public class CustomItemProcessor implements ItemProcessor {
@Override
public Tutorial process(Tutorial item) throws Exception {
System.out.println("Processing..." + item);
return item;
}
}
以下是TutorialRowMapper类，它将数据设置为Tutorial类。
public class TutorialRowMapper implements RowMapper {
@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;
}
}
以下是Tutorial类。这是带有setter和getter方法的简单Java类。在此类中，我们使用批注将此类的方法与XML文件的标记相关联。
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 + "]";
}
}
以下是启动批处理过程的代码。在本课程中，我们将通过运行JobLauncher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());
}
}
在执行此应用程序时，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
这将生成一个具有以下内容的.txt文件。
Report [id=101, title=Learn Java, author=Sanjay, date=06-05-2007]
Report [id=102, title=Learn MySQL, author=Abdul S, date=19-04-2007]
Report [id=103, title=Learn JavaFX, author=Krishna Kasyap, date=06-07-2017]