spring基于注解的声明式事务控制
基于注解的声明式事务控制是基于XML的声明式事务控制，spring基于XML声明式事务控制基于注解的声明式事务控制配置简单，但是配置的通用性不高，基于XML配置的配置比注解繁琐，但是通用性更高！
一、基于注解配置声明式事务的核心配置步骤
1). 核心配置文件applicationContext.xml中导入xmlns:context的约束
2). 其他必要配置
3). 配置事务管理器
DataSourceTransactionManager类中有个属性nestedTransactionAllowed ，表示允许【嵌套事务】，基于此原理，然后再基于切面编程(被代理方法前后增强)，实现嵌套事务！
4). 开启spring对注解的支持
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 配置扫描包路径 -->
<context:component-scan base-package="com.itheima"></context:component-scan>
<!-- 配置jdbcTemplate -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置数据源 -->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql:///spring_01"></property>
<property name="username" value="root"></property>
<property name="password" value="abc123"></property>
</bean>
<!-- 1. 配置事务管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 2.开启spring对注解事务的支持 -->
<tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven>
</beans>
5). 再需要事务支持的地方使用@Transactional注解
@Transactional注解中有很多支持事务特性的属性，与XML配置中的属性如出一辙XML配置声明式事务控制
- propagation: 指定事务的传播级别
- isolation:指定事务隔离级别
- timeout: 指定事务的超时时间
- readOnly: 是否只读
- rollbackFor：异常回滚
...
package com.itheima.service.impl;
import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
@Service("accountService")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public class AccountServiceImpl implements AccountService {
@Autowired
private AccountDao accountDao;
/** @事务
* 转账业务 使用注解进行声明式事务处理，使用
* @Transactional 注解，并在其中配置参数*/
@Override
@Transactional(propagation = Propagation.SUPPORTS, readOnly = false)
public boolean transfer(Integer fromId, Integer toId, Float money) throws Exception {
// 1. 查询原账户余额
Account fromMoney = accountDao.queryMoney(fromId);
if (fromMoney.getMoney() < money) {
throw new RuntimeException("账户余额不足，无法完成转账");
}
// 2. 查询被转入账户的余额
Account toMoney = accountDao.queryMoney(toId);
// 3. 扣除原账户的money
accountDao.updateMoney(fromId, fromMoney.getMoney() - money);
// 显示抛出一个异常。
//int a = 8 / 0;
// 4. 添加被转入账户的余额
accountDao.updateMoney(toId, toMoney.getMoney() + money);
return true;
}
}
二、完整项目代码
1). 项目结构
spring基于注解的声明式事务项目结构.png
2). Account pojo
省略get/set/toString方法
public class Account {
private Integer id;
private String name;
private Float money;
...
3). MyJdbcDaoSupport 抽离的jdbcTemplate
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
/** 如果使用注解开发，需要自己抽离JdbcTemplate */
@Component("myJdbcDaoSupport")
public class MyJdbcDaoSupport {
// 下面这部分就需要在配置文件中进行配置
@Autowired
private JdbcTemplate jdbcTemplate;
public JdbcTemplate getJdbcTemplate() {
return jdbcTemplate;
}
}
4). dao持久层
import com.itheima.domain.Account;
import java.sql.SQLException;
public interface AccountDao {
/** 根据id查询账户的余额 */
public Account queryMoney(Integer id) throws SQLException;
/** 根据id更新账户的余额 */
public int updateMoney(Integer id, Float money) throws SQLException;
}
import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.utils.MyJdbcDaoSupport;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.stereotype.Repository;
import java.sql.SQLException;
@Repository("accountDao")
public class AccountDaoImpl extends MyJdbcDaoSupport implements AccountDao {
/** @事务
* 根据id查询账户的余额，将异常显示抛出 */
@Override
public Account queryMoney(Integer id) throws SQLException {
return super.getJdbcTemplate().queryForObject("select money from account where id = ?",
new BeanPropertyRowMapper<Account>(Account.class), id);
}
/** @事务
* 根据id更新账户的余额, 将异常显示抛出 */
@Override
public int updateMoney(Integer id, Float money) throws SQLException {
return super.getJdbcTemplate().update("update account set money = ? where id = ?",
money, id);
}
}
5). service业务层
public interface AccountService {
/** 转账业务 */
public boolean transfer(Integer fromId, Integer toId, Float money) throws Exception;
}
AccountServiceImpl代码见上面
5). 再需要事务支持的地方使用@Transactional注解
6). Junit4测试代码
import com.itheima.service.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:applicationContext.xml"})
public class MyTest {
@Autowired
private ApplicationContext ac;
/** 转账测试 */
@Test
public void testTransfer() throws Exception {
AccountService service = (AccountService)ac.getBean("accountService");
boolean res = service.transfer(4, 2, 1000F);
System.out.println(res);
}
}
7). maven工程坐标
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.41</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>5.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
<version>5.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>5.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- 切入点表达式解析的jar包 -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.7</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
</dependencies>
