【SSM】Spring集成Mybatis

Spring框架集成Mybtis

  • 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

【SSM】Spring集成Mybatis_第1张图片

  • 第二步:IDEA中创建一个模块,并引入以下依赖
  1. spring-context
  2. spring-jdbc
  3. mysql驱动
  4. mybatis
  5. mybatis-spring:mybatis提供的与spring框架集成的依赖
  6. druid:德鲁伊连接池
  7. junit
    <dependencies>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>6.0.5version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-jdbcartifactId>
            <version>6.0.5version>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>8.0.31version>
        dependency>
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.5.11version>
        dependency>
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatis-springartifactId>
            <version>3.0.1version>
        dependency>
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>druidartifactId>
            <version>1.2.16version>
        dependency>
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.13version>
            <scope>testscope>
        dependency>
    dependencies>
  • 第三步:基于三层架构实现,所以提前创建好所有的包
  1. XXXX.mapper
  2. XXXX.service
  3. XXXX.service.impl
  4. XXXX.bean

【SSM】Spring集成Mybatis_第2张图片

  • 第四步:编写bean
    Account,按bean规范创建

【SSM】Spring集成Mybatis_第3张图片

  • 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

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

DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        
        <setting name="mapUnderscoreToCamelCase" value="false"/>
        
        <setting name="lazyLoadingEnabled" value="true"/>
        
        <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)

<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">

    
    <context:component-scan base-package="com.ncpowernode.spring.service"/>
    
    <context:property-placeholder location="jdbc.properties"/>
    
    <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>
    
    <bean class="org.mybatis.spring.SqlSessionFactoryBean">
        
        <property name="dataSource" ref="dataSource"/>
        
        <property name="typeAliasesPackage" value="com.ncpowernode.spring.bean"/>
        
        <property name="configLocation" value="mybatis-config.xml"/>
    bean>
    
    
    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.ncpowernode.spring.mappers"/>
    bean>
    
    
    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    bean>
    
    
    <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

【SSM】Spring集成Mybatis_第4张图片

【SSM】Spring集成Mybatis_第5张图片

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