将基于XML的声明式事务控制改造成基于注解的声明式事务控制。
1、 创建maven的jar工程,导入依赖。
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.7</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
和事务相关的jar包spring-tx-5.0.2.RELEASE.jar,spring框架为我们提供了一组事务控制的接口。这组接口是在spring-tx-5.0.2.RELEASE.jar 中。
2、创建数据库eesy下的account1表
3、创建Account实体类
public class Account implements Serializable { private Integer id; private String name; private Float money; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Float getMoney() { return money; } public void setMoney(Float money) { this.money = money; } @Override public String toString() { return "Account{" + "id=" + id + ", name='" + name + '\'' + ", money=" + money + '}'; } }
4、编写业务层接口IAccountService
public interface IAccountService {
/**
* 转账
* @param sourceName 转成账户名称
* @param targetName 转入账户名称
* @param money 转账金额
*/
void transfer(String sourceName,String targetName,Float money);
}
5、编写业务层接口的实现类:
@Service("accountService") @Transactional(propagation= Propagation.SUPPORTS,readOnly=true)//只读型事务的配置 public class AccountServiceImpl implements IAccountService{ @Autowired private IAccountDao accountDao;//需要的是读写型事务配置 @Transactional(propagation= Propagation.REQUIRED,readOnly=false) @Override public void transfer(String sourceName, String targetName, Float money) { System.out.println("transfer...."); //2.1根据名称查询转出账户 Account source = accountDao.findAccountByName(sourceName); //2.2根据名称查询转入账户 Account target = accountDao.findAccountByName(targetName); //2.3转出账户减钱 source.setMoney(source.getMoney()-money); //2.4转入账户加钱 target.setMoney(target.getMoney()+money); //2.5更新转出账户 accountDao.updateAccount(source); int i=1/0; //2.6更新转入账户 accountDao.updateAccount(target); } }
service的bean对象可以改造成注解配置@Service(“accountService”),类的成员accountDao可以按类型自动注入@AutoWired。删除set方法。
在需要事务支持的地方(业务层)使用@Transactional注解。
只读型事物的配置:@Transactional(propagation= Propagation.SUPPORTS,readOnly=true)
读写型事务的配置:@Transactional(propagation= Propagation.REQUIRED,readOnly=false)
如果service实现类中有十个方法,正好5个需要读写型,5个需要只读型,配置起来会很麻烦。所示是选择基于XML的声明式事务控制,还是选择基于注解的声明式事务控制,毫无疑问会选择XML,因为XML只需要配置一次就可以一劳永逸的解决所有service的问题。而注解配置的话,你可能在一个service中都需要配置好几遍,因为事务的不同类型,即是只读型还是读写型。
@Transactional注解的传播行为默认是Required,read-only默认为false。这是读写型事务。
6、编写持久层接口:
public interface IAccountDao {
/**
* 根据名称查询账户
* @param accountName
* @return
*/
Account findAccountByName(String accountName);
/**
* 更新账户
* @param account
*/
void updateAccount(Account account);
}
7、编写持久层接口的实现类:
@Repository("accountDao") public class AccountDaoImpl implements IAccountDao { @Autowired private JdbcTemplate jdbcTemplate; @Override public Account findAccountByName(String accountName) { List<Account> accounts = jdbcTemplate.query("select * from account1 where name = ?", new BeanPropertyRowMapper<Account>(Account.class),accountName); if(accounts.isEmpty()){ return null; } if(accounts.size()>1){ throw new RuntimeException("结果集不唯一"); } return accounts.get(0); } @Override public void updateAccount(Account account) { jdbcTemplate.update("update account1 set name=?,money=? where id=?", account.getName(),account.getMoney(),account.getId()); } }
Dao的bean对象可以改造成注解配置@Repository(“accountDao”),类成员JdbcTemplate自动按照类型注入,用@Autowired
8、在bean.xml配置文件中配置bean对象:
<?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:aop="http://www.springframework.org/schema/aop" 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/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- 配置spring创建容器时要扫描的包--> <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://localhost:3306/eesy"></property> <property name="username" value="root"></property> <property name="password" value="123456"></property> </bean> <!-- 配置事务管理器 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 开启spring对注解事务的支持--> <tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven> </beans>
9、测试:发现转账操作实现了事务控制。
@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = "classpath:bean.xml") public class AccountServiceTest { @Autowired private IAccountService as; @Test public void testTransfer(){ as.transfer("aaa","bbb",100f); } }