在本章中，我們將建立一個使用MySQL讀取器和XML Writer的Spring Batch應用程式。
Reader - 在應用程式中使用的讀取器是JdbcCursorItemReader，用於從MySQL資料庫讀取資料。
假設我們在MySQL資料庫中建立了一個表，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)
);
假設已經在其中插入了以下記錄。
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 - 在應用程式中使用的Writer是StaxEventItemWriter，用於將資料寫入XML檔案。
Processor - 在應用程式中使用的處理器是一個自定義處理器，它只是列印從CSV檔案中讀取的記錄。
以下是Spring Batch應用程式的組態檔案。 在這個檔案中，我們將定義Job和Steps。 除此之外，我們還為ItemReader，ItemProcessor和ItemWriter定義了bean。 (在這裡，我們將它們與它們各自的類相關聯，並傳遞所需屬性的值來組態它們。)
<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 = "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>
以下是Spring Batch應用程式的context.xml。 在這個檔案中，我們將定義bean，如作業儲存庫，作業啟動器和事務管理器。
<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 = "123456" />
</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>
以下是處理器類。 在這個類中，我們在應用程式中編寫處理程式碼。 在這裡，列印每條記錄的內容。
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;
}
}
以下是TutorialRowMapper類，它將資料設定為Tutorial類。
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;
}
}
以下是Tutorial類。 它是一個簡單的帶有setter和getter方法的Java類。 在這個類中，我們使用注釋來將這個類的方法與XML檔案的標籤關聯起來。
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 + "]";
}
}
以下是啟動批次處理過程的程式碼。 在這個類中，我們將通過執行JobLauncher來啟動批次處理應用程式。
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());
}
}
在執行這個應用程式時，它將產生以下輸出。
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
這將生成一個包含以下內容的XML檔案。
<?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>