Spring Batch - MySQL 到平面文件
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 − 我们在应用程序中使用的 Reader 是 JdbcCursorItemReader，用于从 MySQL 数据库中读取数据。
假设我们在 MySQL 数据库中创建了一个表，如下所示。
实例
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)。
Processor − 我们在应用程序中使用的处理器是一个自定义处理器，它只打印从 CSV 文件中读取的记录。
jobConfig.xml
以下是我们的示例 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。 除了这些之外，我们还为 ItemReader、ItemProcessor 和 ItemWriter 定义了 bean。 （在这里，我们将它们与各自的类相关联，并传递所需属性的值来配置它们。）
实例
<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 = "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
以下是我们 Spring Batch 应用程序的 context.xml。 在这个文件中，我们将定义像作业存储库、作业启动器和事务管理器这样的 bean。
实例
<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 = "password" />
</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，我们编写应用程序中的处理代码。 在这里，我们打印每条记录的内容。
实例
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。
实例
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。 它是一个带有 setter 和 getter 方法的简单 Java 类。 在这个类中，我们使用注解将这个类的方法与 XML 文件的标签相关联。
实例
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
以下是启动批处理的代码。 在本课程中，我们将通过运行 JobLauncher 来启动批处理应用程序。
实例
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
这将生成一个包含以下内容的 .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]
