Spring集成Mybatis过程详细讲解
目录
- 为啥学习集成Mybatis ORM框架
- 实现步骤
为啥学习集成Mybatis ORM框架
虽然Spring中提供了JDBCTemplate模块,已经很大程度了解决了JDBC代码的复杂度,但它仍然是和Java代码写在一起的。反观 Mybatis 将 Sql 语句写在配置文件中,使得SQL语句和程序实现了松耦合。而且提供了些许标签,使得SQL可以是动态的。在ORM基础上想要更好的用Spring的DI、AOP、事务处理、Junit支持等实现成果,学会使用 Spring 框架集成 Mybatis 是大势所趋。
实现步骤
第一步:准备数据库表
第二步:IDEA中创建一个模块,并引入以下依赖
- spring-context
- spring-jdbc
- mysql驱动
- mybatis
- mybatis-spring:
mybatis提供的
与spring框架集成的依赖 - druid:德鲁伊连接池
- junit
<dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>6.0.5</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>6.0.5</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.31</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.5.11</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>3.0.1</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.2.16</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.13</version> <scope>test</scope> </dependency> </dependencies>
第三步:基于三层架构实现,所以提前创建好所有的包
- XXXX.mapper
- XXXX.service
- XXXX.service.impl
- XXXX.bean
第四步:编写bean
Account,按bean规范创建
第五步:编写Mapper接口
AccountMapper接口,定义与数据库交互的方法
package com.ncpowernode.spring.mappers; import com.ncpowernode.spring.bean.Account; import java.util.List; public interface AccountMapper { List<Account> selectAll(); Account selectByActno(String actno); int insert(Account account); int deleteByActno(String actno); int update(Account account); }
第六步:编写mapper配置文件
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.ncpowernode.spring.mappers.AccountMapper"> <select id="selectAll" resultType="account"> select * from t_act; </select> <insert id="insert"> insert into t_act values(#{actno},#{balance}) </insert> <delete id="deleteByActno"> delete from t_act where actno = #{actno}; </delete> <select id="selectByActno" resultType="account"> select * from t_act where actno = #{actno}; </select> <update id="update"> update t_act set balance = #{balance} where actno = #{actno}; </update> </mapper>
第七步:编写service接口和service接口的实现类
service接口
package com.ncpowernode.spring.service; import com.ncpowernode.spring.bean.Account; import java.util.List; public interface AccountService { int save(Account act); int deleteByActno(String actno); List<Account> getAll(); void transfer(String fromActno,String toActno,double money); }
service实现
package com.ncpowernode.spring.service.impl; import com.ncpowernode.spring.bean.Account; import com.ncpowernode.spring.mappers.AccountMapper; import com.ncpowernode.spring.service.AccountService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import java.util.List; @Service("accountService") @Transactional public class AccountServiceImpl implements AccountService { @Autowired @Qualifier("accountMapper") private AccountMapper accountMapper; @Override public int save(Account act) { return accountMapper.insert(act); } @Override public int deleteByActno(String actno) { return accountMapper.deleteByActno(actno); } @Override public List<Account> getAll() { return accountMapper.selectAll(); } @Override public void transfer(String fromActno, String toActno, double money) { // 判断余额 Account fromAccount = accountMapper.selectByActno(fromActno); if (fromAccount.getBalance()<money) throw new RuntimeException("余额不足"); // 更新数据库 Account toAccount = accountMapper.selectByActno(toActno); fromAccount.setBalance(fromAccount.getBalance()-money); toAccount.setBalance(toAccount.getBalance()+money); int cnt = accountMapper.update(fromAccount); cnt += accountMapper.update(toAccount); // 判断业务是否实现成功 if(cnt!=2) throw new RuntimeException("转账失败"); } }
第八步:编写jdbc.properties配置文件
数据库连接池相关信息
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/???
jdbc.username=???
jdbc.password=???
第九步:编写mybatis-config.xml核心配置文件
<?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> <settings> <!--驼峰命名自动映射,默认false--> <setting name="mapUnderscoreToCamelCase" value="false"/> <!--设置懒加载--> <setting name="lazyLoadingEnabled" value="true"/> <!--配置日志,可以帮助我们查看sql执行信息--> <setting name="logImpl" value="STDOUT_LOGGING"/> </settings> </configuration>
第十步:编写spring.xml配置文件
组件扫描
引入外部的属性文件
数据源
SqlSessionFactoryBean配置(注入mybatis核心配置文件路径,指明别名包,注入数据源)
Mapper扫描配置器(指定扫描的包)
事务管理器(DataSourceTransactionManager,注入数据源)
启动事务注解(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 http://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.ncpowernode.spring.service"/> <!--引入外部的属性文件--> <context:property-placeholder location="jdbc.properties"/> <!--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"/> <!--指定别名包--> <property name="typeAliasesPackage" value="com.ncpowernode.spring.bean"/> <!--指定mybatis核心配置文件--> <property name="configLocation" value="mybatis-config.xml"/> </bean> <!--配置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.ncpowernode.spring.mappers"/> </bean> <!--事务管理器--> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> </bean> <!--启动事务注解--> <tx:annotation-driven transaction-manager="txManager"/> </beans>
第十一步:编写测试程序,并添加事务,进行测试。
@Test public void testSM(){ ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml"); AccountService accountService = applicationContext.getBean("accountService", AccountServiceImpl.class); accountService.getAll().forEach(System.out::println); accountService.transfer("act-001","act-002",10000.0); }
测试结果
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