Spring 事务管理示例 JDBC

Spring 事务管理是 Spring 框架中使用最广泛、最重要的特性之一。事务管理在任何企业应用程序中都是一项简单的任务。我们已经学习了如何使用JDBC API 进行事务管理。Spring 为事务管理提供了广泛的支持，帮助开发人员将更多精力放在业务逻辑上，而不必担心系统发生故障时数据的完整性。

Spring 事务管理

使用 Spring 事务管理的一些好处包括：

1. 支持声明式事务管理。在此模型中，Spring 使用 AOP 替代事务方法来提供数据完整性。这是首选方法，并且在大多数情况下都有效。
2. 支持大多数事务 API，如 JDBC、Hibernate、JPA、JDO、JTA 等。我们需要做的就是使用适当的事务管理器实现类。例如，org.springframework.jdbc.datasource.DriverManagerDataSource对于 JDBC 事务管理，org.springframework.orm.hibernate3.HibernateTransactionManager如果我们使用 Hibernate 作为 ORM 工具。
3. TransactionTemplate通过使用或实现来支持程序化事务管理PlatformTransactionManager。

声明式事务管理支持事务管理器中我们需要的大多数功能，因此我们将在示例项目中使用这种方法。

Spring 事务管理 JDBC 示例

我们将创建一个简单的 Spring JDBC 项目，我们将在单个事务中更新多个表。仅当所有 JDBC 语句成功执行时，事务才应提交，否则应回滚以避免数据不一致。如果您了解 JDBC 事务管理，您可能会认为我们可以通过将连接的自动提交设置为 false 来轻松完成此操作，并根据所有语句的结果提交或回滚事务。显然我们可以做到这一点，但这会导致大量仅用于事务管理的样板代码。此外，相同的代码将出现在我们寻找事务管理的所有地方，导致紧密耦合和不可维护的代码。Spring 声明式事务管理通过使用面向方面编程来解决这些问题，以实现松散耦合并避免在我们的应用程序中使用样板代码。让我们通过一个简单的示例看看 Spring 是如何做到这一点的。在我们进入我们的 Spring 项目之前，让我们做一些数据库设置以供我们使用。

Spring 事务管理 - 数据库设置

我们将创建两个表供我们使用，并在单个事务中更新它们。

CREATE TABLE `Customer` (
  `id` int(11) unsigned NOT NULL,
  `name` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `Address` (
  `id` int(11) unsigned NOT NULL,
  `address` varchar(20) DEFAULT NULL,
  `country` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

We could define foreign-key relationship here from Address id column to Customer id column, but for simplicity I am not having any constraint defined here. Our Database setup is ready for spring transaction management project, lets create a simple Spring Maven Project in the Spring Tool Suite. Our final project structure will look like below image. Let’s look into each of the pieces one by one, together they will provide a simple spring transaction management example with JDBC.

Spring Transaction Management - Maven Dependencies

Since we are using JDBC API, we would have to include spring-jdbc dependency in our application. We would also need MySQL database driver to connect to mysql database, so we will include mysql-connector-java dependency too. spring-tx artifact provides transaction management dependencies, usually it’s included automatically by STS but if it’s not then you need to include it too. You might see some other dependencies for logging and unit testing, however we will not be using any of them. Our final pom.xml file looks like below code.

<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>org.springframework.samples</groupId>
	<artifactId>SpringJDBCTransactionManagement</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<properties>

		<!-- Generic properties -->
		<java.version>1.7</java.version>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

		<!-- Spring -->
		<spring-framework.version>4.0.2.RELEASE</spring-framework.version>

		<!-- Logging -->
		<logback.version>1.0.13</logback.version>
		<slf4j.version>1.7.5</slf4j.version>

		<!-- Test -->
		<junit.version>4.11</junit.version>

	</properties>

	<dependencies>
		<!-- Spring and Transactions -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${spring-framework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-tx</artifactId>
			<version>${spring-framework.version}</version>
		</dependency>

		<!-- Spring JDBC and MySQL Driver -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-jdbc</artifactId>
			<version>${spring-framework.version}</version>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.0.5</version>
		</dependency>

		<!-- Logging with SLF4J & LogBack -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>${slf4j.version}</version>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>ch.qos.logback</groupId>
			<artifactId>logback-classic</artifactId>
			<version>${logback.version}</version>
			<scope>runtime</scope>
		</dependency>

		<!-- Test Artifacts -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-test</artifactId>
			<version>${spring-framework.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>${junit.version}</version>
			<scope>test</scope>
		</dependency>

	</dependencies>
</project>

I have updated the Spring versions to the latest one as of today. Make sure MySQL database driver is compatible with your mysql installation.

Spring Transaction Management - Model Classes

We will create two Java Beans, Customer and Address that will map to our tables.

package com.journaldev.spring.jdbc.model;

public class Address {

	private int id;
	private String address;
	private String country;

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public String getCountry() {
		return country;
	}
	public void setCountry(String country) {
		this.country = country;
	}

}

package com.journaldev.spring.jdbc.model;

public class Customer {

	private int id;
	private String name;
	private Address address;

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Address getAddress() {
		return address;
	}
	public void setAddress(Address address) {
		this.address = address;
	}

}

Notice that Customer bean has Address as one of it’s variables. When we will implement DAO for Customer, we will get data for both customer and address table and we will execute two separate insert queries for these tables and that’s why we need transaction management to avoid data inconsistency.

Spring Transaction Management - DAO Implementation

Let’s implement the DAO for Customer bean, for simplicity we will just have one method to insert record in both customer and address tables.

package com.journaldev.spring.jdbc.dao;

import com.journaldev.spring.jdbc.model.Customer;

public interface CustomerDAO {

	public void create(Customer customer);
}

package com.journaldev.spring.jdbc.dao;

import javax.sql.DataSource;

import org.springframework.jdbc.core.JdbcTemplate;

import com.journaldev.spring.jdbc.model.Customer;

public class CustomerDAOImpl implements CustomerDAO {

	private DataSource dataSource;

	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}

	@Override
	public void create(Customer customer) {
		String queryCustomer = "insert into Customer (id, name) values (?,?)";
		String queryAddress = "insert into Address (id, address,country) values (?,?,?)";

		JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

		jdbcTemplate.update(queryCustomer, new Object[] { customer.getId(),
				customer.getName() });
		System.out.println("Inserted into Customer Table Successfully");
		jdbcTemplate.update(queryAddress, new Object[] { customer.getId(),
				customer.getAddress().getAddress(),
				customer.getAddress().getCountry() });
		System.out.println("Inserted into Address Table Successfully");
	}

}

Notice that CustomerDAO implementation is not taking care of transaction management. This way we are achieving separation of concerns because sometimes we get DAO implementations from third party and we don’t have control on these classes.

Spring Declarative Transaction Management - Service

Let’s create a Customer Service that will use the CustomerDAO implementation and provide transaction management when inserting records in the customer and address tables in a single method.

package com.journaldev.spring.jdbc.service;

import com.journaldev.spring.jdbc.model.Customer;

public interface CustomerManager {

	public void createCustomer(Customer cust);
}

package com.journaldev.spring.jdbc.service;

import org.springframework.transaction.annotation.Transactional;

import com.journaldev.spring.jdbc.dao.CustomerDAO;
import com.journaldev.spring.jdbc.model.Customer;

public class CustomerManagerImpl implements CustomerManager {

	private CustomerDAO customerDAO;

	public void setCustomerDAO(CustomerDAO customerDAO) {
		this.customerDAO = customerDAO;
	}

	@Override
	@Transactional
	public void createCustomer(Customer cust) {
		customerDAO.create(cust);
	}

}

If you notice the CustomerManager implementation, it’s just using CustomerDAO implementation to create the customer but provide declarative transaction management through annotating createCustomer() method with @Transactional annotation. That’s all we need to do in our code to get the benefits of Spring transaction management. @Transactional annotation can be applied over methods as well as whole class. If you want all your methods to have transaction management features, you should annotate your class with this annotation. Read more about annotations at Java Annotations Tutorial. The only part remaining is wiring spring beans to get spring transaction management example to work.

Spring Transaction Management - Bean Configuration

Create a Spring Bean Configuration file with name as “spring.xml”. We will use this in our test program to wire spring beans and execute our JDBC program to test transaction management.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="https://www.springframework.org/schema/beans"
	xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xmlns:context="https://www.springframework.org/schema/context"
	xmlns:tx="https://www.springframework.org/schema/tx"
	xsi:schemaLocation="https://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
		https://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context-4.0.xsd
		https://www.springframework.org/schema/tx https://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

	<!-- Enable Annotation based Declarative Transaction Management -->
	<tx:annotation-driven proxy-target-class="true"
		transaction-manager="transactionManager" />

	<!-- Creating TransactionManager Bean, since JDBC we are creating of type
		DataSourceTransactionManager -->
	<bean id="transactionManager"
		class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource" />
	</bean>

	<!-- MySQL DB DataSource -->
	<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/TestDB" />
		<property name="username" value="pankaj" />
		<property name="password" value="pankaj123" />
	</bean>

	<bean id="customerDAO" class="com.journaldev.spring.jdbc.dao.CustomerDAOImpl">
		<property name="dataSource" ref="dataSource"></property>
	</bean>

	<bean id="customerManager" class="com.journaldev.spring.jdbc.service.CustomerManagerImpl">
		<property name="customerDAO" ref="customerDAO"></property>
	</bean>

</beans>

Important points to note in the spring bean configuration file are:

• tx:annotation-driven element is used to tell Spring context that we are using annotation based transaction management configuration. transaction-manager attribute is used to provide the transaction manager bean name. transaction-manager default value is transactionManager but I am still having it to avoid confusion. proxy-target-class attribute is used to tell Spring context to use class based proxies, without it you will get runtime exception with message such as Exception in thread “main” org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named ‘customerManager’ must be of type [com.journaldev.spring.jdbc.service.CustomerManagerImpl], but was actually of type [com.sun.proxy.$Proxy6]
• Since we are using JDBC, we are creating transactionManager bean of type org.springframework.jdbc.datasource.DataSourceTransactionManager. This is very important and we should use proper transaction manager implementation class based on our transaction API use.
• dataSource bean is used to create the DataSource object and we are required to provide the database configuration properties such as driverClassName, url, username and password. Change these values based on your local settings.
• We are injecting dataSource into customerDAO bean. Similarly we are injecting customerDAO bean into customerManager bean definition.

Our setup is ready, let’s create a simple test class to test our transaction management implementation.

package com.journaldev.spring.jdbc.main;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.journaldev.spring.jdbc.model.Address;
import com.journaldev.spring.jdbc.model.Customer;
import com.journaldev.spring.jdbc.service.CustomerManager;
import com.journaldev.spring.jdbc.service.CustomerManagerImpl;

public class TransactionManagerMain {

	public static void main(String[] args) {
		ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(
				"spring.xml");

		CustomerManager customerManager = ctx.getBean("customerManager",
				CustomerManagerImpl.class);

		Customer cust = createDummyCustomer();
		customerManager.createCustomer(cust);

		ctx.close();
	}

	private static Customer createDummyCustomer() {
		Customer customer = new Customer();
		customer.setId(2);
		customer.setName("Pankaj");
		Address address = new Address();
		address.setId(2);
		address.setCountry("India");
		// setting value more than 20 chars, so that SQLException occurs
		address.setAddress("Albany Dr, San Jose, CA 95129");
		customer.setAddress(address);
		return customer;
	}

}

Notice that I am explicitly setting address column value too long so that we will get exception while inserting data into Address table. Now when we run our test program, we get following output.

Mar 29, 2014 7:59:32 PM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3fa99295: startup date [Sat Mar 29 19:59:32 PDT 2014]; root of context hierarchy
Mar 29, 2014 7:59:32 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [spring.xml]
Mar 29, 2014 7:59:32 PM org.springframework.jdbc.datasource.DriverManagerDataSource setDriverClassName
INFO: Loaded JDBC driver: com.mysql.jdbc.Driver
Inserted into Customer Table Successfully
Mar 29, 2014 7:59:32 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml]
Mar 29, 2014 7:59:32 PM org.springframework.jdbc.support.SQLErrorCodesFactory <init>
INFO: SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase]
Exception in thread "main" org.springframework.dao.DataIntegrityViolationException: PreparedStatementCallback; SQL [insert into Address (id, address,country) values (?,?,?)]; Data truncation: Data too long for column 'address' at row 1; nested exception is com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data too long for column 'address' at row 1
	at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:100)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:658)
	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:907)
	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:968)
	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:978)
	at com.journaldev.spring.jdbc.dao.CustomerDAOImpl.create(CustomerDAOImpl.java:27)
	at com.journaldev.spring.jdbc.service.CustomerManagerImpl.createCustomer(CustomerManagerImpl.java:19)
	at com.journaldev.spring.jdbc.service.CustomerManagerImpl$$FastClassBySpringCGLIB$$84f71441.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:711)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:644)
	at com.journaldev.spring.jdbc.service.CustomerManagerImpl$$EnhancerBySpringCGLIB$$891ec7ac.createCustomer(<generated>)
	at com.journaldev.spring.jdbc.main.TransactionManagerMain.main(TransactionManagerMain.java:20)
Caused by: com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data too long for column 'address' at row 1
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2939)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1623)
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1715)
	at com.mysql.jdbc.Connection.execSQL(Connection.java:3249)
	at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1268)
	at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1541)
	at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1455)
	at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1440)
	at org.springframework.jdbc.core.JdbcTemplate$2.doInPreparedStatement(JdbcTemplate.java:914)
	at org.springframework.jdbc.core.JdbcTemplate$2.doInPreparedStatement(JdbcTemplate.java:907)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:642)
	... 16 more

请注意，日志消息表明数据已成功插入客户表，但 MySQL 数据库驱动程序抛出的异常明确表明该值对于地址列来说太长。现在，如果您检查客户表，您将找不到任何行，这意味着事务已完全回滚。如果您想知道事务管理魔法发生在哪里，请仔细查看日志并注意 Spring 框架创建的 AOP 和代理类。Spring 框架正在使用 Around 建议为 CustomerManagerImpl 生成代理类，并且仅在方法成功返回时才提交事务。如果有任何异常，它只会回滚整个事务。我建议您阅读Spring AOP 示例以了解有关面向方面编程模型的更多信息。这就是 Spring 事务管理示例的全部内容，请从以下链接下载示例项目并试用它以了解更多信息。

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