spring事务管理（xml配置）与spring自带连接数据库JdbcTemplate

　　什么是事务，很通俗的话来说就是，我们日常生活中总会出现在银行转账的业务，加入A向B转账100元，此时A的账户中应该减少100元，B的账户中增加100元，但是如果在A转完账B还没有接受的时候，服务器出现了故障，一般银行的系统都会给出交易失败的提示，并且A的账户中总金额也不会变，那么这就类似一个事务。

　　1.事务是单个逻辑单元工作单位执行的一系列操作

　　2.多个操作作为整体向系统提交，要么都执行，要么都不执行

　　3.事务时一个不可分割的逻辑单元

事务的4大特性：原子性、一致性、隔离性、持久性（ACID）

下边我就模拟一个银行转账的事务：

首先导入依赖

<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-expression -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!--以上4个是spring的核心-->
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjrt -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.9.2</version>
        </dependency>
        <!--以上两个是aop依赖-->
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <!--spring自带的数据库连接依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <!--mysql数据库依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>

dao层接口

　　

 public interface AccountDao {
     void addmonkey();//向表中增加金额
     void submonkey();//向表中减少金额
 }

dao层实现类

 //dao层实现类需要继承JdbcDaoSupport，这是spring自带的数据库操作
 public class AccountDaoImpl extends JdbcDaoSupport implements AccountDao {
     @Override
     public void addmonkey() {
         //id为1的用户总金额增加100
         String sql="update account set accountmonkey=accountmonkey+100 where accountid=1";
         this.getJdbcTemplate().update(sql);
     }

     @Override
     public void submonkey() {
         //id为2的用户总金额减少100
         String sql="update account set accountmonkey=accountmonkey-100 where accountid=2";
         this.getJdbcTemplate().update(sql);
     }
 }

service层接口

public interface AccountService {
    void changeMonkey();
}

service实现类

public class AccountServiceImpl implements AccountService {
    private AccountDao dao;
    @Override
    public void changeMonkey() {
        dao.submonkey();//A先转账给B
        int result=5/0;//模拟异常，再调用完加钱的时候。
        dao.addmonkey();//B接收money
    }

    public AccountDao getDao() {
        return dao;
    }

    public void setDao(AccountDao dao) {
        this.dao = dao;
    }
}

实体类

 public class Account {
     private int accountid;
     private String accountname;
     private Double accountmonkey;
     //省略set，get方法
 }

增强类

//增强类
public class BeforeAdvice implements MethodBeforeAdvice, AfterReturningAdvice {
    @Override
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println("前置增强");
    }

    @Override
    public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
        System.out.println("后置增强");
    }
}

测试类

 public class Test {
     public static void main(String[] args) {
         ApplicationContext context = new ClassPathXmlApplicationContext("/applictionContext.xml");
         AccountService bean = context.getBean(AccountService.class);
         bean.changeMonkey();
     }
 }

核心配置文件applicationContext.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" xmlns:tx="http://www.springframework.org/schema/tx"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop"
        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 http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
     <!--引入外部文件，将数据库配置文件引入到本文件中-->
     <context:property-placeholder location="classpath:database.properties"/>
     <!--dao层-->
     <bean id="dao" class="dao.impl.AccountDaoImpl">
         <!--注入数据源-->
         <property name="dataSource" ref="dataSource"/>
     </bean>
     <!--向容器中添加service层实现类-->
     <bean id="service" class="service.impl.AccountServiceImpl">
         <property name="dao" ref="dao"/>
     </bean>
     <!--向容器中添加通知的实现类-->
     <bean id="advice1" class="advice.BeforeAdvice"></bean>
     <!--顾问包装通知-->
     <bean id="advisor" class="org.springframework.aop.support.NameMatchMethodPointcutAdvisor">
         <property name="advice" ref="advice1"/>
         <property name="mappedName" value="say"/>
     </bean>
     <!--顾问代理生成器-->
     <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
         <property name="beanNames" value="service"/>
         <property name="interceptorNames" value="advisor"/>
     </bean>
     <!--数据源，使用的数据源是spring自带的，讲道理这个自带的数据源不怎么好-->
     <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
         <property name="username" value="${jdbc.username}"/>
         <property name="password" value="${jdbc.password}"/>
         <property name="url" value="${jdbc.url}"/>
         <property name="driverClassName" value="${jdbc.driver}"/>
     </bean>
     <!--配置事务管理器-->
     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
         <property name="dataSource" ref="dataSource"/>
     </bean>
     <!--通知，tx标签是配置事务用的。propagation:事物的管理级别，isolation:事务的传播行为-->
     <tx:advice transaction-manager="transactionManager" id="ad" >
         <tx:attributes>
             <tx:method name="changeMonkey" propagation="REQUIRED" isolation="READ_COMMITTED"/>
         </tx:attributes>
     </tx:advice>
     <aop:config>
         <aop:pointcut id="pointcut" expression="execution(* service.*.*(..))"/>
         <aop:advisor advice-ref="ad" pointcut-ref="pointcut"/>
     </aop:config>
 </beans>

这里呢一个简单的事务就已经配置好了。