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一、实现步骤

1、准备数据库表

t_act：银行账户

2、在IDEA中创建一个模块，并引入依赖

• spring-context
• spring-jdbc
• mysql驱动
• mybatis
• mybatis-spring mybatis提供的与spring框架集成的依赖
• 德鲁伊连接池
• junit

为什么有了mybatis驱动还需要jdbc？
因为事务tx在jdbc包里

  <dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.32</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.5.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.2.5.RELEASE</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.6</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.1</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.0.20</version></dependency></dependencies>

3、基于三层架构实现

创建所有的包
com.powernode.bank.pojo
com.powernode.bank.mapper
com.powernode.bank.service
com.powernode.bank.service.impl

4、编写pojo

Account:属性私有化，提供公开的setter getter toString

public class Account {private String actno;private double balance;public Account(String actno, double balance) {this.actno = actno;this.balance = balance;}public Account() {}public String getActno() {return actno;}public void setActno(String actno) {this.actno = actno;}public double getBalance() {return balance;}public void setBalance(double balance) {this.balance = balance;}@Overridepublic String toString() {return "Account{" +"actno='" + actno + '\'' +", balance=" + balance +'}';}
}

5、编写mapper接口

AccountMapper接口，定义方法

public interface AccountMapper {//该接口的实现类不需要写，是mybatis通过动态代理机制生成的实现类//查询所有的账户List<Account> seleteAllAccount();//根据actno查询指定账户Account selectByActno(String actno);//增加账户int insertAccount(Account account);//删除账户int deleteByActno(String actno);//修改账户int update(Account account);
}

6、编写mapper配置文件

在配置文件中配置命名空间，以及每一个方法对应的SQL

< mapper namespace=“com.powernode.bank.mapper.AccountMapper” >

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""https://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.powernode.bank.mapper.AccountMapper"><select id="selectAllAccount" resultType="account">select * from t_act</select><select id="selectByActno" resultType="account">select * from t_actwhere actno=#{actno};</select><insert id="insertAccount">insert into t_actvalues(#{actno},#{balance})</insert><delete id="deleteByActno">delete from t_actwhere actno=#{actno}</delete><update id="update">update t_actset balance=#{balance} where actno=#{actno}</update></mapper>

7、编写service接口和service接口的实现类

AccountService

public interface AccountService {//业务接口int save(Account account);int deleteByActno(String actno);int modify(Account account);Account getByActno(String actno);List<Account> getAll();void transfer(String fromActno,String toActno,double money);
}

AccountServiceImpl
注意一定要进行AccountServiceImpl Bean实例化：@Service(“accountService”)

以及一定要注入AccountMapper Bean注入： @Autowired

@Service("accountService")
public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountMapper mapper;@Overridepublic int save(Account account) {int i = mapper.insertAccount(account);return i;}@Overridepublic int deleteByActno(String actno) {int i = mapper.deleteByActno(actno);return i;}@Overridepublic int modify(Account account) {mapper.update(account);return 0;}@Overridepublic Account getByActno(String actno) {return mapper.selectByActno(actno);}@Overridepublic List<Account> getAll() {return mapper.seleteAllAccount();}@Overridepublic void transfer(String fromActno, String toActno, double money) {Account fromAct = mapper.selectByActno(fromActno);Account toAct = mapper.selectByActno(toActno);if(fromAct.getBalance()<money){throw new RuntimeException("余额不足");}fromAct.setBalance(fromAct.getBalance()-money);toAct.setBalance(toAct.getBalance()+money);int count = mapper.update(fromAct);count += mapper.update(toAct);if(count==2){System.out.println("转账成功");}else{throw new RuntimeException("转账失败");}}
}

8、编写jdbc.properties配置文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/dududu?useSSL=false
jdbc.username=root
jdbc.password=123456

9、编写mybatis-config.xml配置文件

这个文件可以没有，大部分的配置可以转移到spring配置文件中
如果遇到mybatis相关的系统级配置，还是需要这个文件

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--设置日志输出语句,显示相应操作的sql语名--><settings><setting name="logImpl" value="STDOUT_LOGGING"/></settings>
</configuration>

10、编写spring.xml配置文件【配置地狱】

1、组件扫描
2、引入外部的属性文件
3、数据源
4、SqlSessionFactoryBean配置

注入mybatis核心配置文件
指定别名包
注入数据源

5、Mapper扫描配置器（主要扫描mapper接口生成代理类）

扫描指定的包

6、事务管理器 DataSourceTransactionManager

注入数据源

7、启用事务注解【启用之后在业务实现类当中添加注解@Transactional 事务才会起作用】

注入事务管理器

<?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/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"><!--组件扫描--><!--<context:component-scan base-package="com.powernode.bank"/>--><!--在spring的核心配置文件中引入其他的子spring配置文件--><context:component-scan base-package="com.powernode.bank"></context:component-scan><context:property-placeholder location="jdbc.properties"></context:property-placeholder><!--数据源--><bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"><property name="driverClassName" value="${jdbc.driver}"/><property name="url" value="${jdbc.url}"/><property name="username" value="${jdbc.username}"/><property name="password" value="${jdbc.password}"/></bean><!--配置SqlSessionFactoryBean--><bean class="org.mybatis.spring.SqlSessionFactoryBean"><!--注入数据源--><property name="dataSource" ref="dataSource"/><!--指定mybatis核心配置文件--><property name="configLocation" value="mybatis-config.xml"/><!--指定别名--><property name="typeAliasesPackage" value="com.powernode.bank.pojo"/></bean><!--Mapper扫描配置器，主要扫描Mapper接口，生成代理类--><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.powernode.bank.mapper"/></bean><!--事务管理器--><bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!--启用事务注解--><tx:annotation-driven transaction-manager="txManager"/></beans>

11、编写测试程序，添加事务，进行测试

    @Testpublic void testSM(){ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");AccountService accountService =  ac.getBean("accountService",AccountService.class);//accountService.transfer("act_001","act_002",2000);accountService.save(new Account("act_005",20));List<Account> AccountList =  accountService.getAll();AccountList.forEach(list->{System.out.println("账号为："+list.getActno()+",账户余额为："+list.getBalance());});}

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