本篇内容介绍了“Spring怎么使用注解和配置文件配置事务”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
使用注解配置事务:
package com.atguigu.spring.tx; public interface BookShopDao { //根据书号获取书的单价 public int findBookPriceByIsbn(String isbn); //更新数的库存. 使书号对应的库存 - 1 public void updateBookStock(String isbn); //更新用户的账户余额: 使 username 的 balance - price public void updateUserAccount(String username, int price); }
package com.atguigu.spring.tx; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.stereotype.Repository; @Repository("bookShopDao") public class BookShopDaoImpl implements BookShopDao { @Autowired private JdbcTemplate jdbcTemplate; @Override public int findBookPriceByIsbn(String isbn) { String sql = "SELECT price FROM book WHERE isbn = ?"; return jdbcTemplate.queryForObject(sql, Integer.class, isbn); } @Override public void updateBookStock(String isbn) { //检查书的库存是否足够, 若不够, 则抛出异常 String sql2 = "SELECT stock FROM book_stock WHERE isbn = ?"; int stock = jdbcTemplate.queryForObject(sql2, Integer.class, isbn); if(stock == 0){ throw new BookStockException("库存不足!"); } String sql = "UPDATE book_stock SET stock = stock -1 WHERE isbn = ?"; jdbcTemplate.update(sql, isbn); } @Override public void updateUserAccount(String username, int price) { //验证余额是否足够, 若不足, 则抛出异常 String sql2 = "SELECT balance FROM account WHERE username = ?"; int balance = jdbcTemplate.queryForObject(sql2, Integer.class, username); if(balance < price){ throw new UserAccountException("余额不足!"); } String sql = "UPDATE account SET balance = balance - ? WHERE username = ?"; jdbcTemplate.update(sql, price, username); } }
package com.atguigu.spring.tx; public interface BookShopService { public void purchase(String username, String isbn); }
事务配置的核心部分:
package com.atguigu.spring.tx; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Isolation; import org.springframework.transaction.annotation.Propagation; import org.springframework.transaction.annotation.Transactional; @Service("bookShopService") public class BookShopServiceImpl implements BookShopService { @Autowired private BookShopDao bookShopDao; //添加事务注解 //1.使用 propagation 指定事务的传播行为, 即当前的事务方法被另外一个事务方法调用时 //REQUIRED:为默认取值, 被调用的事务一个执行失败整个大事务就回滚 //REQUIRES_NEW:调用的事务如果执行成功就保存结果不会被回滚,其他事务执行失败不会影响到它 //2.使用 isolation 指定事务的隔离级别, 最常用的取值为 READ_COMMITTED //3.默认情况下 Spring 的声明式事务对所有的运行时异常进行回滚. 也可以通过对应的 //属性进行设置. 通常情况下取默认值即可. //4.使用 readOnly 指定事务是否为只读. 表示这个事务只读取数据但不更新数据, //这样可以帮助数据库引擎优化事务. 若方法只读取数据库值, 应设置 readOnly=true //5.使用 timeout 指定事务最多可以占用的时间,若超过时间则强制回滚 // @Transactional(propagation=Propagation.REQUIRES_NEW, // isolation=Isolation.READ_COMMITTED, // noRollbackFor={UserAccountException.class}) @Transactional(propagation=Propagation.REQUIRES_NEW, isolation=Isolation.READ_COMMITTED, readOnly=false, timeout=3) @Override public void purchase(String username, String isbn) { try { Thread.sleep(5000); } catch (InterruptedException e) {} //1. 获取书的单价 int price = bookShopDao.findBookPriceByIsbn(isbn); //2. 更新数的库存 bookShopDao.updateBookStock(isbn); //3. 更新用户余额 bookShopDao.updateUserAccount(username, price); } }
package com.atguigu.spring.tx; import java.util.List; public interface Cashier { public void checkout(String username, List<String> isbns); }
package com.atguigu.spring.tx; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; @Service("cashier") public class CashierImpl implements Cashier { @Autowired private BookShopService bookShopService; @Transactional @Override public void checkout(String username, List<String> isbns) { for(String isbn: isbns){ bookShopService.purchase(username, isbn); } } }
package com.atguigu.spring.tx; import static org.junit.Assert.*; import java.util.Arrays; import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class SpringTransactionTest { private ApplicationContext ctx = null; private BookShopDao bookShopDao = null; private BookShopService bookShopService = null; private Cashier cashier = null; { ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); bookShopDao = ctx.getBean(BookShopDao.class); bookShopService = ctx.getBean(BookShopService.class); cashier = ctx.getBean(Cashier.class); } @Test public void testTransactionlPropagation(){ cashier.checkout("AA", Arrays.asList("1001", "1002")); } @Test public void testBookShopService(){ bookShopService.purchase("AA", "1001"); } @Test public void testBookShopDaoUpdateUserAccount(){ bookShopDao.updateUserAccount("AA", 200); } @Test public void testBookShopDaoUpdateBookStock(){ bookShopDao.updateBookStock("1001"); } @Test public void testBookShopDaoFindPriceByIsbn() { System.out.println(bookShopDao.findBookPriceByIsbn("1001")); } }
BookStockException、UserAccountException为自定义异常类!
配置文件:
<?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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" 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-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> <context:component-scan base-package="com.atguigu.spring"></context:component-scan> <!-- 导入资源文件 --> <context:property-placeholder location="classpath:db.properties"/> <!-- 配置 C3P0 数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="user" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property> <property name="driverClass" value="${jdbc.driverClass}"></property> <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property> <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property> </bean> <!-- 配置 Spirng 的 JdbcTemplate --> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 配置 NamedParameterJdbcTemplate, 该对象可以使用具名参数, 其没有无参数的构造器, 所以必须为其构造器指定参数 --> <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate"> <constructor-arg ref="dataSource"></constructor-arg> </bean> <!-- 配置事务管理器 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 启用事务注解 --> <tx:annotation-driven transaction-manager="transactionManager"/> </beans>
配置文件(使用配置文件配置事务,以上类的注解需要全部删除):
<?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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd 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-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> <context:component-scan base-package="com.atguigu.spring"></context:component-scan> <!-- 导入资源文件 --> <context:property-placeholder location="classpath:db.properties"/> <!-- 配置 C3P0 数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="user" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property> <property name="driverClass" value="${jdbc.driverClass}"></property> <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property> <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property> </bean> <!-- 配置 Spirng 的 JdbcTemplate --> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 配置 bean --> <bean id="bookShopDao" class="com.atguigu.spring.tx.xml.BookShopDaoImpl"> <property name="jdbcTemplate" ref="jdbcTemplate"></property> </bean> <bean id="bookShopService" class="com.atguigu.spring.tx.xml.service.impl.BookShopServiceImpl"> <property name="bookShopDao" ref="bookShopDao"></property> </bean> <bean id="cashier" class="com.atguigu.spring.tx.xml.service.impl.CashierImpl"> <property name="bookShopService" ref="bookShopService"></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. 配置事务属性 --> <tx:advice id="txAdvice" transaction-manager="transactionManager"> <tx:attributes> <!-- 根据方法名指定事务的属性 --> <tx:method name="purchase" propagation="REQUIRES_NEW"/> <tx:method name="get*" read-only="true"/> <tx:method name="find*" read-only="true"/> <tx:method name="*"/> </tx:attributes> </tx:advice> <!-- 3. 配置事务切入点, 以及把事务切入点和事务属性关联起来 --> <aop:config> <aop:pointcut expression="execution(* com.atguigu.spring.tx.xml.service.*.*(..))" id="txPointCut"/> <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/> </aop:config> </beans>
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