spring之集成Mybatis

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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;
    }

    @Override
    public 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 mapper
        PUBLIC "-//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_act
        where actno=#{actno};
    </select>

    <insert id="insertAccount">
        insert into t_act
        values(#{actno},#{balance})
    </insert>

    <delete id="deleteByActno">
        delete from t_act
        where actno=#{actno}
    </delete>

    <update id="update">
        update t_act
        set 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 {
    @Autowired
    private AccountMapper mapper;
    @Override
    public int save(Account account) {
        int i = mapper.insertAccount(account);
        return i;
    }

    @Override
    public int deleteByActno(String actno) {
        int i = mapper.deleteByActno(actno);
        return i;
    }

    @Override
    public int modify(Account account) {
        mapper.update(account);
        return 0;
    }

    @Override
    public Account getByActno(String actno) {
        return mapper.selectByActno(actno);
    }

    @Override
    public List<Account> getAll() {
        return mapper.seleteAllAccount();
    }

    @Override
    public 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

    @Test
    public 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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