峰Spring4学习（8）spring对事务的支持

一、事务简介：

二、编程式事务管理：

例子

1、需求：模拟转账，张三向李四转账50元；

数据库中存在t_count表：

代码实现：

BankDao.java:

package com.cy.dao;

public interface BankDao {
    //转入money元
    public void inMoney(int money,int userId);
    
    //转出money元
    public void outMoney(int money,int userId);
}

BankDaoImpl.java:

package com.cy.dao.impl;

import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;

import com.cy.dao.BankDao;

public class BankDaoImpl implements BankDao {
    
    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

    public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {
        this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
    }
    
    //userId转入money元
    @Override
    public void inMoney(int money, int userId) {
        String sql = "update t_count set count = count + :money where userId = :userId";
        MapSqlParameterSource sps = new MapSqlParameterSource();
        sps.addValue("money", money)
            .addValue("userId", userId);
        namedParameterJdbcTemplate.update(sql, sps);
    }
    
    //userId转出money元
    @Override
    public void outMoney(int money, int userId) {
        String sql = "update t_count set count = count - :money where userId = :userId";
        MapSqlParameterSource sps = new MapSqlParameterSource();
        sps.addValue("money", money)
            .addValue("userId", userId);
        namedParameterJdbcTemplate.update(sql, sps);
    }

}

BankService.java:

package com.cy.service;

public interface BankService {
    
    /**
     * A向B转账count元
     * @param count
     * @param userIdA
     * @param userIdB
     */
    public void transferAccounts(int count, int userIdA, int userIdB);
}

BankServiceImpl.java:

package com.cy.service.impl;

import com.cy.dao.BankDao;
import com.cy.service.BankService;

public class BankServiceImpl implements BankService {
    
    private BankDao bankDao;
    
    
    public void setBankDao(BankDao bankDao) {
        this.bankDao = bankDao;
    }
    
    //A向B转账count元
    @Override
    public void transferAccounts(int count, int userIdA, int userIdB) {
        bankDao.outMoney(count, userIdA);
        bankDao.inMoney(count, userIdB);
    }

}

beans.xml配置：

<?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: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/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">
        
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>
    </bean>
    
    <bean id="bankDao" class="com.cy.dao.impl.BankDaoImpl">
        <property name="namedParameterJdbcTemplate" ref="namedParameterJdbcTemplate"></property>
    </bean> 
    
    <bean id="bankService" class="com.cy.service.impl.BankServiceImpl">
        <property name="bankDao" ref="bankDao"></property>
    </bean> 
    
</beans>

测试代码：

package com.cy.test;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.cy.service.BankService;

public class T {
    private ApplicationContext ac;
    
    @Before
    public void setUp() throws Exception {
        ac=new ClassPathXmlApplicationContext("beans.xml");
    }
    
    //测试代码
    @Test
    public void transferAccounts() {
        BankService bankService = (BankService)ac.getBean("bankService");
        bankService.transferAccounts(50, 1, 2);
    }
    
}

 

2、上面程序运行是没问题的，张三向李四转50元，张三账户为450元，李四账户为550元。

模拟一种异常情况：

inMoney中将t_count改为t_count2,这张表不存在，张三转出50元，李四没有收到。这时需要事务回滚；

将上面代码修改为如下：

1）BankDaoImpl.java中构建t_count2不存在，无法完成转入，会抛出异常：

//userId转入money元
    @Override
    public void inMoney(int money, int userId) {
        String sql = "update t_count2 set count = count + :money where userId = :userId";
        MapSqlParameterSource sps = new MapSqlParameterSource();
        sps.addValue("money", money)
            .addValue("userId", userId);
        namedParameterJdbcTemplate.update(sql, sps);
    }

2）BankServiceImpl.java中使用编程式事务管理：

package com.cy.service.impl;

import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallbackWithoutResult;
import org.springframework.transaction.support.TransactionTemplate;

import com.cy.dao.BankDao;
import com.cy.service.BankService;

public class BankServiceImpl implements BankService {
    
    private BankDao bankDao;
    
    private TransactionTemplate transactionTemplate;
    
    public void setTransactionTemplate(TransactionTemplate transactionTemplate) {
        this.transactionTemplate = transactionTemplate;
    }

    public void setBankDao(BankDao bankDao) {
        this.bankDao = bankDao;
    }
    
    //A向B转账count元
    @Override
    public void transferAccounts(final int count, final int userIdA, final int userIdB) {
        transactionTemplate.execute(new TransactionCallbackWithoutResult(){

            @Override
            protected void doInTransactionWithoutResult(TransactionStatus arg0) {
                bankDao.outMoney(count, userIdA);
                bankDao.inMoney(count, userIdB);
            }
        });
    }

}

3)beans.xml中配置jdbc事务管理器、transactionTemplate:

<?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: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/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">
        
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <!-- jdbc事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <bean id="transactionTemplate" class="org.springframework.transaction.support.TransactionTemplate">
        <property name="transactionManager" ref="transactionManager"></property>
    </bean>
    
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>
    </bean>
    
    <bean id="bankDao" class="com.cy.dao.impl.BankDaoImpl">
        <property name="namedParameterJdbcTemplate" ref="namedParameterJdbcTemplate"></property>
    </bean> 
    
    <bean id="bankService" class="com.cy.service.impl.BankServiceImpl">
        <property name="bankDao" ref="bankDao"></property>
        <property name="transactionTemplate" ref="transactionTemplate"></property>
    </bean> 
    
</beans>

运行测试程序，报错，但是张三账户中仍然是500元，李四账户中没有收到钱，为500元。事务进行了回滚。

 

 三、声明式事务管理：

上面编程式事务管理的缺点：

非业务代码已经嵌入到业务代码里面，转账的业务代码就两句。控制事务的代码和业务代码混在一起，不太好。

 

声明式事务管理：

使用spring的AOP，面向切面，把事务切进去；

1.使用xml配置声明式事务：

BankServiceImpl.java:

package com.cy.service.impl;

import com.cy.dao.BankDao;
import com.cy.service.BankService;

public class BankServiceImpl implements BankService {
    
    private BankDao bankDao;
    
    public void setBankDao(BankDao bankDao) {
        this.bankDao = bankDao;
    }
    
    //A向B转账count元
    @Override
    public void transferAccounts(final int count, final int userIdA, final int userIdB) {
        bankDao.outMoney(count, userIdA);
        bankDao.inMoney(count, userIdB);
    }

}

beans.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:aop="http://www.springframework.org/schema/aop"
    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/aop
        http://www.springframework.org/schema/aop/spring-aop.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">
        
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <!-- jdbc事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- 配置事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*"/>
        </tx:attributes>
    </tx:advice>
    
    <!-- 配置事务切面 -->
    <aop:config>
        <!-- 配置切点 -->
        <aop:pointcut id="serviceMethod" expression="execution(* com.cy.service.*.*(..))" />
        <!-- 配置事务通知 -->
        <aop:advisor advice-ref="txAdvice" pointcut-ref="serviceMethod"/>
    </aop:config>
    
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>
    </bean>
    
    <bean id="bankDao" class="com.cy.dao.impl.BankDaoImpl">
        <property name="namedParameterJdbcTemplate" ref="namedParameterJdbcTemplate"></property>
    </bean> 
    
    <bean id="bankService" class="com.cy.service.impl.BankServiceImpl">
        <property name="bankDao" ref="bankDao"></property>
    </bean> 
    
</beans>

运行测试代码，事务得到回滚。

2.使用注解配置声明式事务：

 BankServiceImpl.java:

package com.cy.service.impl;

import org.springframework.transaction.annotation.Transactional;

import com.cy.dao.BankDao;
import com.cy.service.BankService;

@Transactional
public class BankServiceImpl implements BankService {
    
    private BankDao bankDao;
    
    public void setBankDao(BankDao bankDao) {
        this.bankDao = bankDao;
    }
    
    //A向B转账count元
    @Override
    public void transferAccounts(final int count, final int userIdA, final int userIdB) {
        bankDao.outMoney(count, userIdA);
        bankDao.inMoney(count, userIdB);
    }

}

beans.xml配置：

<?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: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/aop
        http://www.springframework.org/schema/aop/spring-aop.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">
        
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <!-- jdbc事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <tx:annotation-driven transaction-manager="transactionManager"/>
    
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>
    </bean>
    
    <bean id="bankDao" class="com.cy.dao.impl.BankDaoImpl">
        <property name="namedParameterJdbcTemplate" ref="namedParameterJdbcTemplate"></property>
    </bean> 
    
    <bean id="bankService" class="com.cy.service.impl.BankServiceImpl">
        <property name="bankDao" ref="bankDao"></property>
    </bean> 
    
</beans>

四、事务的传播行为：

 

read-only:只读的；

例如将上面xml中的事务通知修改为配置如下：

beans.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:aop="http://www.springframework.org/schema/aop"
    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/aop
        http://www.springframework.org/schema/aop/spring-aop.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">
        
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <!-- jdbc事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- 配置事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="insert*" propagation="REQUIRED" />
            <tx:method name="update*" propagation="REQUIRED" />
            <tx:method name="edit*" propagation="REQUIRED" />
            <tx:method name="save*" propagation="REQUIRED" />
            <tx:method name="add*" propagation="REQUIRED" />
            <tx:method name="new*" propagation="REQUIRED" />
            <tx:method name="set*" propagation="REQUIRED" />
            <tx:method name="remove*" propagation="REQUIRED" />
            <tx:method name="delete*" propagation="REQUIRED" />
            <tx:method name="change*" propagation="REQUIRED" />
            <tx:method name="get*" propagation="REQUIRED" read-only="true" />
            <tx:method name="find*" propagation="REQUIRED" read-only="true" />
            <tx:method name="load*" propagation="REQUIRED" read-only="true" />
            <tx:method name="transferAccounts" propagation="REQUIRED" />
            <tx:method name="*" propagation="REQUIRED" read-only="true" />
        </tx:attributes>
    </tx:advice>
    
    <!-- 配置事务切面 -->
    <aop:config>
        <!-- 配置切点 -->
        <aop:pointcut id="serviceMethod" expression="execution(* com.cy.service.*.*(..))" />
        <!-- 配置事务通知 -->
        <aop:advisor advice-ref="txAdvice" pointcut-ref="serviceMethod"/>
    </aop:config>
    
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>
    </bean>
    
    <bean id="bankDao" class="com.cy.dao.impl.BankDaoImpl">
        <property name="namedParameterJdbcTemplate" ref="namedParameterJdbcTemplate"></property>
    </bean> 
    
    <bean id="bankService" class="com.cy.service.impl.BankServiceImpl">
        <property name="bankDao" ref="bankDao"></property>
    </bean> 
    
</beans>

 

 

 

 

 

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