Spring综合实战——实现转账业务

一、简单实现基本业务

1、new一个web project

2、加入必备的jar包（如下图）、配置log4j.properties、db.properties文件

3、数据库，数据表准备

4、创建一个AccountDao接口和其实现类AccountDaoImpl

AccountDao.java

package com.hy.spring.dao;

public interface AccountDao {

	void addMoney(Integer id, double money);
	void subMoney(Integer id, double money);
}

AccountDaoImpl.java

package com.hy.spring.dao.impl;

import javax.annotation.Resource;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import com.hy.spring.dao.AccountDao;


@Repository("accountDao")
public class AccountDaoImpl  implements AccountDao{

	@Resource(name="jdbcTemplate")
	private JdbcTemplate jtemplate;
	
	@Override
	public void addMoney(Integer id, double money) {
		String sql = "update account set acccount = acccount + ? where id = ?";
		jtemplate.update(sql,money,id);	
	}

	@Override
	public void subMoney(Integer id, double money) {
		String sql = "update account set acccount = acccount - ? where id = ?";
		jtemplate.update(sql,money,id);
	}

}

5、创建Service

AccountService.java

package com.hy.spring.service;

public interface AccountService {

       public void transfer(Integer from, Integer to, double money);
 
}

AccountServiceImpl.java

package com.hy.spring.service.impl;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import com.hy.spring.dao.AccountDao;
import com.hy.spring.service.AccountService;

@Service("accountService")
public class AccountServiceImpl implements AccountService{

	@Resource(name="accountDao")
	private AccountDao accountDao;
	
	@Override
	public void transfer(Integer from, Integer to, double money) {
		accountDao.subMoney(from, money);
		accountDao.addMoney(to, money);
	}
}

6、配置applicationContex.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:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.0.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
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd">
        
         <!-- 使用注解方式 -->
        <context:component-scan base-package="com.hy.spring.dao"></context:component-scan>
         <context:component-scan base-package="com.hy.spring.service"></context:component-scan>
        
        <context:property-placeholder location="classpath:db.properties"/>
        <!-- 配置连接池 -->
        <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="driverClass" value="${jdbc.driverClass}"></property>
             <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
        </bean>
        
        
        <!-- JdbcTemplate配置 --> 
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
             <property name="dataSource" ref="dataSource"></property>
        </bean>
       
        <!-- 配置事务管理器 -->
        <bean name="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
             <property name="dataSource" ref="dataSource"></property>
        </bean>
        
</beans>        

7、添加测试用例

AccountTest.java

package com.hy.spring.service;


import javax.annotation.Resource;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class AccountTest {

	@Resource(name="accountService")
	private AccountService accountService;
	
	@Test
	public void test() {
		accountService.transfer(1, 2, 10000.02);		
	}
}

二、优化

出现的问题：

如果我们在AccountServiceImpl.java中的subMoney和addMoney之间加入一个异常操作，例如：int a = 10/0；，发现上述案例的转账方钱变少了，但是被转账账户的钱没有增加。

优化

添加事务处理，在applicationContext.xml中配置事务处理，添加如下代码，java代码不用修改就能实现对这个异常的处理

<!-- 配置事务管理器 -->
         <bean name="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
             <property name="dataSource" ref="dataSource"></property>
        </bean>
         
        <!-- 配置通知 -->
         <tx:advice id="txAdvice" transaction-manager="transactionManager">
             <tx:attributes>
             <!--     传播行为 -->
                 <tx:method name="transfer" propagation="REQUIRED"/>
                 <!-- 常用举例，本题暂时未用到以下情况 -->
                 <tx:method name="save*" propagation="REQUIRED"/>
                 <tx:method name="delete*" propagation="REQUIRED"/>
                 <tx:method name="drop*" propagation="REQUIRED"/>
                 <tx:method name="search*" propagation="SUPPORTS" read-only="true"/>
              </tx:attributes>
        </tx:advice> 
       <!-- 将通知织入切入点 -->
       <aop:config>
              <!--  切入点 -->
               <aop:pointcut expression="execution(public void com.hy.spring.service.impl.AccountServiceImpl.*(..))" id="txPointcut"/>
               <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointcut"/>
       </aop:config>

总结：

1、还需要深入理解AOP，
2、注解方式和xml文件配置方式使用还是不熟练，
3、对Spring的框架还需要深入了解