1.概述, 事务管理, 编程式和说明式事务管理
2. 事务属性
传播行为:
传播行为 |
意义 |
PROPAGATION_MANDATORY |
该方法必须运行在一个事务中。如果当前事务不存在,将抛出一个异常。 |
PROPAGATION_NESTED |
若当前已经存在一个事务,则该方法应当运行在一个嵌套的事务中。被嵌套的事务可以从当前事务中单独的提交或回滚。若当前事务不存在,则看起来就和PROPAGATION_REQUIRED没有两样。 |
PROPAGATION_NEVER |
当前的方法不应该运行在一个事务上下文中。如果当前存在一个事务,则会抛出一个异常。 |
PROPAGATION_NOT_SUPPORTED |
表示该方法不应在事务中运行。如果一个现有的事务正在运行,他将在该方法的运行期间被挂起。如果使用jta的事务管理器,需要访问jtatansactionmanager. |
传播行为 |
意义 |
PROPAGATION_REQUIRED |
表示当前方法必须运行在一个事务中。若一个现有的事务正在进行中,该方法将会运行在这个事务中。否则的话,就要开一个新的事务。 |
PROPAGATION_REQUIRES_NEW |
表示当前方法必须运行在它自己的事务里。他将启动一个新的事务。如果一个现有事务在运行的话,将在这个方法运行期间被挂起。若使用jtaTransactionManager,则需要访问transactionManager |
PROPAGATION_SUPPORTS |
当前方法不需要事务处理环境,但如果有一个事务已经在运行的话,这个方法也可以在这个事务里运行。 |
隔离级别
隔离级别 |
含义 |
ISOlATION_DEFAULT |
使用后端数据库默认的隔离级别 |
ISOLATION_READ_UNCOMMITED |
允许你读取还未提交后数据。可能导致脏、幻、不可重服 |
ISOLATION_READ_COMMITTED |
允许在并发事务已经提交后读取。可防止脏读,但幻读和 不可重复读仍可发生。 |
ISOLATION_REPEATABLE_READ |
对相同字段的多次读取是一致的,除非数据被事务本身改变。可防止脏、不可重复读,幻读仍可能发生。 |
ISOLATION_SERIALABLE |
完全服从ACID的隔离级别,确保不发生脏、幻、不可重复读。这在所有的隔离级别中是最慢的,它是典型的通过完全锁定在事务中涉及的数据表来完成的。 |
只读
若对数据库只进行读操作,可设置事务只读的属性,使用某些优化措施。数据库会进行优化处理。若使用hibernate作为持久化机制,声明一个只读事务会使hibernate的flush模式设置为FLUSH_NEVER。避免不必要的数据同步,将所有更新延迟到事务的结束。
事务超时
若事务在长时间的运行,会不必要的占用数据库资源。设置超时后,会在指定的时间片回滚。将那些具有可能启动新事务的传播行为的方法的事务设置超时才有意义(PROPAGATION_REQUIRED,PROPAGATION_REQUIRES_NEW,PROPAGATION_NESTED)。
回滚规则
3. 示例代码
Customer.java, javabean 对象
public class Customer { private Integer id ; private String name ; private Integer age ; 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 Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } }
Customer.hbm.xml ,映射配置文件
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="cn.itcast.spring.domain.Customer" table="customers" lazy="false"> <id name="id" column="id" type="integer"> <generator class="identity" /> </id> <property name="name" column="name" type="string" not-null="true"/> <property name="age" column="age" type="integer" /> </class> </hibernate-mapping>
CustomerDao.java, dao层接口
public interface CustomerDao { public void insertCustomer(Customer c); public void updateCustomer(Customer c); public List<Customer> findCustomerByName(String name); //批量保存 //public void saveCustomers(List<Customer> list); }
CustomerDaoImpl.java,dao接口 模板实现
/** * CustomerDaoImpl */ public class CustomerDaoImpl implements CustomerDao { //hibernate模板,封装样板代码 private HibernateTemplate ht ; public void setHt(HibernateTemplate ht) { this.ht = ht; } public List<Customer> findCustomerByName(String name) { String hql = "from Customer c where c.name = ?"; return ht.find(hql, name); } public void insertCustomer(Customer c) { ht.save(c); } public void updateCustomer(Customer c) { ht.update(c); } /** * 批量保存 */ // public void saveCustomers(final List<Customer> list) { // ht.execute(new HibernateCallback(){ // public Object doInHibernate(Session session) // throws HibernateException, SQLException { // Transaction tx = null; // try { // tx = session.beginTransaction(); // for(Customer c : list){ // session.save(c); // } // tx.commit(); // } catch (Exception e) { // tx.rollback(); // e.printStackTrace(); // } // return null; // }}); // } }
CustomerDaoSupportImpl.java , dao接口 HibernateDaoSupport 实现
/** * CustomerDaoImpl */ public class CustomerDaoSupportImpl extends HibernateDaoSupport implements CustomerDao { public List<Customer> findCustomerByName(String name) { String hql = "from Customer c where c.name = ?"; return getHibernateTemplate().find(hql, name); } public void insertCustomer(Customer c) { getHibernateTemplate().save(c); } public void updateCustomer(Customer c) { getHibernateTemplate().update(c); } public void saveCustomers(List<Customer> list) { // TODO Auto-generated method stub } }
CustomerService.java,service层接口
public interface CustomerService { public void insertCustomer(Customer c); public void updateCustomer(Customer c); public List<Customer> findCustomerByName(String name); //批量保存 public void saveCustomers(List<Customer> list); }
CustomerServiceImpl.java, service层接口实现, 编程式事务管理
public class CustomerServiceImpl implements CustomerService { //dao private CustomerDao dao ; //事务模板,封装事务管理的样板代码 private TransactionTemplate tt ; //注入事务模板 public void setTt(TransactionTemplate tt) { this.tt = tt; } //注入dao public void setDao(CustomerDao dao) { this.dao = dao; } public List<Customer> findCustomerByName(String name) { return dao.findCustomerByName(name); } public void insertCustomer(Customer c) { dao.insertCustomer(c); } /** * 批量保存, 编程式事务管理 */ public void saveCustomers(final List<Customer> list) { // for(Customer c : list){ // dao.insertCustomer(c); // } tt.execute(new TransactionCallback(){ public Object doInTransaction(TransactionStatus status) { try { for(Customer c : list){ dao.insertCustomer(c); } } catch (RuntimeException e) { e.printStackTrace(); //设置回滚 status.setRollbackOnly(); } return null; }}); } public void updateCustomer(Customer c) { dao.updateCustomer(c); } }
CustomerServiceDeclareImpl.java , service层接口实现, 声明式事务管理
/** * 声明式事务管理,通过aop框架实现 */ public class CustomerServiceDeclareImpl implements CustomerService { //dao private CustomerDao dao ; //注入dao public void setDao(CustomerDao dao) { this.dao = dao; } public List<Customer> findCustomerByName(String name) { return dao.findCustomerByName(name); } public void insertCustomer(Customer c) { dao.insertCustomer(c); } /** * 批量保存, 编程式事务管理 */ public void saveCustomers(final List<Customer> list) { for(Customer c : list){ dao.insertCustomer(c); } } public void updateCustomer(Customer c) { dao.updateCustomer(c); } }
jdbc.properties, 数据库配置信息
jdbc.driverclass=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/spring jdbc.username=root jdbc.password=root c3p0.pool.size.max=10 c3p0.pool.size.min=2 c3p0.pool.size.ini=3 c3p0.pool.size.increment=2 hibernate.dialect=org.hibernate.dialect.MySQL5Dialect hibernate.show_sql=true hibernate.hbm2ddl.auto=none
sh.xml, spring配置文件,编程式
<?xml version="1.0"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd "> <!-- 指定分散配置的文件的位置 --> <context:property-placeholder location="classpath:cn/itcast/spring/hibernate/jdbc.properties"/> <!-- 配置c3p0数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="${jdbc.driverclass}" /> <property name="jdbcUrl" value="${jdbc.url}" /> <property name="user" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> <property name="maxPoolSize" value="${c3p0.pool.size.max}" /> <property name="minPoolSize" value="${c3p0.pool.size.min}" /> <property name="initialPoolSize" value="${c3p0.pool.size.ini}" /> <property name="acquireIncrement" value="${c3p0.pool.size.increment}" /> </bean> <!-- 本地回话工厂bean,spring整合hibernate的核心入口 --> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <!-- 指定hibernate自身的属性 --> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">${hibernate.dialect}</prop> <prop key="hibernate.show_sql">${hibernate.show_sql}</prop> <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop> </props> </property> <!-- 方式一:映射资源文件的位置 <property name="mappingResources"> <list> <value>classpath:cn/itcast/spring/domain/Customer.hbm.xml</value> </list> </property> --> <!--方式二--> <property name="mappingDirectoryLocations"> <list> <value>classpath:cn/itcast/spring/domain</value> </list> </property> <!--方式二:使用hibernate自身的配置文件配置 <property name="configLocations"> <list> <value>classpath:hibernate.cfg.xml</value> </list> </property> --> </bean> <!-- hibernate模板,封装样板代码 --> <bean id="ht" class="org.springframework.orm.hibernate3.HibernateTemplate"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <!-- customerDao --> <bean id="customerDao" class="cn.itcast.spring.hibernate.CustomerDaoImpl"> <property name="ht" ref="ht" /> </bean> <!-- hibernate事务管理器,在service层面上实现事务管理,而且达到平台无关性 --> <bean id="htm" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <!-- 事务模板,封装了事务管理的样板代码 --> <bean id="tt" class="org.springframework.transaction.support.TransactionTemplate"> <property name="transactionManager" ref="htm" /> </bean> <!-- customerService --> <bean id="customerService" class="cn.itcast.spring.hibernate.CustomerServiceImpl"> <property name="dao" ref="customerDao" /> <property name="tt" ref="tt" /> </bean> <!-- ************************ daoSupport ******************** --> <bean id="customerDaoSupport" class="cn.itcast.spring.hibernate.CustomerDaoSupportImpl"> <property name="sessionFactory" ref="sessionFactory" /> </bean> </beans>
shDeclare.xml, spring配置文件,声明式
<?xml version="1.0"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd "> <!-- 指定分散配置的文件的位置 --> <context:property-placeholder location="classpath:cn/itcast/spring/hibernate/jdbc.properties"/> <!-- 配置c3p0数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="${jdbc.driverclass}" /> <property name="jdbcUrl" value="${jdbc.url}" /> <property name="user" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> <property name="maxPoolSize" value="${c3p0.pool.size.max}" /> <property name="minPoolSize" value="${c3p0.pool.size.min}" /> <property name="initialPoolSize" value="${c3p0.pool.size.ini}" /> <property name="acquireIncrement" value="${c3p0.pool.size.increment}" /> </bean> <!-- 本地回话工厂bean,spring整合hibernate的核心入口 --> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <!-- 指定hibernate自身的属性 --> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">${hibernate.dialect}</prop> <prop key="hibernate.show_sql">${hibernate.show_sql}</prop> <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop> </props> </property> <!-- 映射资源文件的位置 <property name="mappingResources"> <list> <value>classpath:cn/itcast/spring/domain/Customer.hbm.xml</value> </list> </property> --> <property name="mappingDirectoryLocations"> <list> <value>classpath:cn/itcast/spring/domain</value> </list> </property> <!-- 使用hibernate自身的配置文件配置 <property name="configLocations"> <list> <value>classpath:hibernate.cfg.xml</value> </list> </property> --> </bean> <!-- hibernate模板,封装样板代码 --> <bean id="ht" class="org.springframework.orm.hibernate3.HibernateTemplate"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <!-- customerDao --> <bean id="customerDao" class="cn.itcast.spring.hibernate.CustomerDaoImpl"> <property name="ht" ref="ht" /> </bean> <!-- hibernate事务管理器,在service层面上实现事务管理,而且达到平台无关性 --> <bean id="htm" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <!-- customerService,目标对象 --> <bean id="customerServiceTarget" class="cn.itcast.spring.hibernate.CustomerServiceDeclareImpl"> <property name="dao" ref="customerDao" /> </bean> <!-- 代理对象 --> <bean id="customerService" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"> <!-- 注入事务管理器 --> <property name="transactionManager" ref="htm" /> <property name="proxyInterfaces"> <list> <value>cn.itcast.spring.hibernate.CustomerService</value> </list> </property> <property name="target" ref="customerServiceTarget" /> <!-- 事务属性集(设置事务策略的), 事务属性:传播行为,隔离级别,只读,超时,回滚规则 --> <property name="transactionAttributes"> <props> <prop key="save*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT</prop> <prop key="update*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT</prop> <prop key="delete*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT</prop> <prop key="insert*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT</prop> <!--对数据库只进行读操作,可设置事务只读的属性,使用某些优化措施。数据库会进行优化处理。--> <prop key="load*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly</prop> <prop key="get*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly</prop> <prop key="find*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly</prop> <prop key="*">PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly</prop> </props> </property> </bean> </beans>
AppService.java 测试代码1
public class AppService { public static void main(String[] args) throws SQLException { ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/spring/hibernate/sh.xml"); CustomerService cs = (CustomerService) ac.getBean("customerService"); List<Customer> list = new ArrayList<Customer>(); Customer c = null ; for(int i = 0 ; i < 10 ; i++){ c = new Customer(); if(i == 9){ c.setName(null); } else{ c.setName("tom" + i); } c.setAge(20 + i); list.add(c); } cs.saveCustomers(list); } }
AppServiceDeclare.java 测试代码二
public class AppServiceDeclare { public static void main(String[] args) throws SQLException { ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/spring/hibernate/shDeclare.xml"); CustomerService cs = (CustomerService) ac.getBean("customerService"); List<Customer> list = new ArrayList<Customer>(); Customer c = null ; for(int i = 0 ; i < 10 ; i++){ c = new Customer(); if(i == 9){ c.setName(null); } else{ c.setName("tom" + i); } c.setAge(20 + i); list.add(c); } cs.saveCustomers(list); } }