spring 编程式事务

好多东西网上都有,事务的特点就不说了, 直接来个简单的列子比较好.
spring中事务有两种实现方式, 一种是编程式事务, 一种是声明式事务
我个人来说喜欢用编程式事务, 总感觉明了一些, 可能只是习惯吧
新建一个springDemo项目

image.png

dao

public interface AccountDao {
    /**
     * 汇款
     * @param outer 汇款人
     * @param money 汇款金额
     */
    public void out(String outer,int money);

    /**
     * 收款
     * @param inner 收款人
     * @param money 收款金额
     */
    public void in(String inner,int money);
}

dao实现类

package dao.impl;

import dao.AccountDao;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class AccountDaoImpl extends JdbcDaoSupport implements AccountDao {

    /**
     * 根据用户名减少账户金额
     */
    public void out(String outer, int money) {
        this.getJdbcTemplate().update("update account set money = money - ? where username = ?",money,outer);
    }

    /**
     * 根据用户名增加账户金额
     */
    public void in(String inner, int money) {
        this.getJdbcTemplate().update("update account set money = money + ? where username = ?",money,inner);
    }
}

service

package service;

public interface AccountService {
    /**
     * 转账
     * @param outer 汇款人
     * @param inner 收款人
     * @param money 交易金额
     */
    public void transfer(String outer,String inner,int money);
}

service是实现类

package service.impl;

import dao.AccountDao;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallbackWithoutResult;
import org.springframework.transaction.support.TransactionTemplate;
import service.AccountService;

public class AccountServiceImpl implements AccountService {
    private AccountDao accountDao;
    private TransactionTemplate transactionTemplate;

    public void setAccountDao(AccountDao accountDao) {
        this.accountDao = accountDao;
    }

    public void setTransactionTemplate(TransactionTemplate transactionTemplate) {
        this.transactionTemplate = transactionTemplate;
    }

    public void transfer(final String outer, final String inner, final int money) {
        transactionTemplate.execute(new TransactionCallbackWithoutResult() {
            @Override
            protected void doInTransactionWithoutResult(TransactionStatus arg0) {
                accountDao.out(outer, money);
                //int i = 1/0;
                accountDao.in(inner, money);
            }
        });
    }
}

在代码中需要用到TransactionTemplate模版, TransactionTemplate需要在xml中进行配置, 否则是不行的, 至于为什么需要配置 , 大家都是干这个的,应该能想到

在resources新建一个applicationContextTranscation.xml

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

    <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/test?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <bean id="accountDao" class="dao.impl.AccountDaoImpl">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="accountService" class="service.impl.AccountServiceImpl">
        <property name="accountDao" ref="accountDao"></property>
        <property name="transactionTemplate" ref="transactionTemplate"></property>
    </bean>

    <!--事务模版-->
    <bean id="transactionTemplate" class="org.springframework.transaction.support.TransactionTemplate">
        <property name="transactionManager" ref="txManager"></property>
    </bean>

    <!--数据源事务管理器-->
    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
</beans>

事务模版和数据源管理器都有自己的property , 都已经实现ioc注入
TransactionTemplate必须指定transactionManager
DataSourceTransactionManager必须指定数据源dataSource

ok, 现在进行测试:

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import service.AccountService;

public class TransctionTest {
    @Test
    public void testNoTransaction(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContextTranscation.xml");
        AccountService account = (AccountService) context.getBean("accountService");
        //Tom 向 Marry 转账1000
        account.transfer("Tom", "Marry", 1000);
    }
}

上述用到的数据库

CREATE TABLE `account` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) DEFAULT NULL,
  `money` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of account
-- ----------------------------
INSERT INTO `account` VALUES ('1', 'Tom', '8000');
INSERT INTO `account` VALUES ('2', 'Marry', '12000');