Spring学习（五）Spring和Mybatis的整合

2023-08-23 17:35:16

1、前言

在整合之前、要搞清楚是谁整合谁、后续会学到很多整合的例子。在这里、是Spring整合Mybatis、Spring中集成了很多关于Mybatis中一些关键类的jar包、通过这些、可以更加方便的联系Mybatis和数据库之间的关系。以前、Mybatis操作数据库的思路是这样的SqlSessionFactory -> SqlSession ->StudentMapper ->CRUD。可以发现 ，MyBatis最终是通过SqlSessionFactory来操作数据库。Spring整合MyBatis 其实就是将MyBatis的SqlSessionFactory 交给Spring

2、项目骨架

3、步骤

1、下载相关的jar包

点击我下载

2、创建实体类和表

3、配置MyBatis配置文件conf.xml

其实里面没用到啥东西、单纯需要配一下。

<?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>

    <!--   数据库信息  -->

    <!--  加载映射文件  -->

<!--    <mappers>-->

<!--        <mapper resource="com/feng/mapper/studentMapper.xml"></mapper>-->

<!--    </mappers>-->

</configuration>

4、通过mapper.xml将类、表建立映射关系

studentMapper

package com.feng.mapper;

import com.feng.enetity.Student;

public interface StudentMapper {

    public void addStudent(Student student);

}

studentMapper.xml

<?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">

<!--namespace：该mapper.xml映射文件的唯一标识-->

<mapper namespace="com.feng.mapper.StudentMapper">

    <select id="queryStudentByStuNo" parameterType="int" resultType="com.feng.enetity.Student">

        select * from student where stuno = #{stuNo}

    </select>

    <insert id="addStudent" parameterType="com.feng.enetity.Student">

        insert into student(stuno, stuname, stuage) values(#{stuNo},#{stuName},#{stuAge})

    </insert>

</mapper>

5、Spring管理SqlSessionFactory

之前使用MyBatis: conf.xml ->SqlSessionFacotry .现在整合的时候，需要通过Spring管理SqlSessionFacotry ，因此产生qlSessionFacotry 所需要的数据库信息不在放入conf.xml,而需要放入spring配置文件中配置Spring配置文件（applicationContext.xml）.

applicationContext.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"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!-- 加载db.properties文件 -->

    <bean id="config" class="org.springframework.beans.factory.config.PreferencesPlaceholderConfigurer">

        <property name="locations">

            <array>

                <value>classpath:db.properties</value>

            </array>

        </property>

    </bean>

    <!--    配置数据库信息（替代mybatis的conf.xml）    -->

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">

        <property name="driverClassName" value="${driver}"></property>

        <property name="url" value="${url}"></property>

        <property name="username" value="${username}"></property>

        <property name="password" value="${password}"></property>

    </bean>

    <!--  在SpringIoc容器中创建Mybatis核心类SqlSessionFactory  -->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

        <property name="dataSource" ref="dataSource"></property>

        <!-- 加载Mybatis配置文件 -->

        <property name="configLocation" value="classpath:conf.xml"></property>

        <!-- 加载mapper.xml路径 -->

        <property name="mapperLocations" value="com/feng/mapper/*.xml"></property>

    </bean>

    <bean id="studentMapper" class="com.feng.dao.impl.StudentDaoImpl">

        <!--将Spring配置的sqlSessionFactory 对象交给mapper(dao)-->

        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>

    </bean>

    <bean id="studentService" class="com.feng.service.impl.StudentServiceImpl">

        <property name="studentMapper" ref="studentMapper"></property>

    </bean>

</beans>

6、使用Spring-Mybatis整合产物开发程序

目标：通过sprin*生mybatis最终操作需要的动态mapper对象(StudentMapper对象)、Sprin*生动态mapper对象有3种方法：

a.第一种方式

DAO层实现类继承 SqlSessionDaoSupport类SqlSessionDaoSupport类提供了一个属性 SqlSession

b.第二种方式

就是省略掉第一种方式的实现类、直接MyBatis提供的 Mapper实现类：org.mybatis.spring.mapper.MapperFactoryBean 。缺点：每个mapper都需要一个配置一次

c.第三种方式

批量配置实现类

注：本文用的是第一种方式。

7、三层架构实现

1、Dao层

StudentDaoImpl

package com.feng.dao.impl;

import com.feng.mapper.StudentMapper;

import com.feng.enetity.Student;

import org.apache.ibatis.session.SqlSession;

import org.mybatis.spring.support.SqlSessionDaoSupport;

public class StudentDaoImpl extends SqlSessionDaoSupport implements StudentMapper {

    @Override

    public void addStudent(Student student) {

        SqlSession session = super.getSqlSession();

        StudentMapper stuDao = session.getMapper(StudentMapper.class);

        stuDao.addStudent(student);

    }

}

2、Service层

1、接口IStudentService

package com.feng.service;

import com.feng.enetity.Student;

public interface IStudentService {

    public void addStudent(Student student);

}

2、实现类StudentServiceImpl

package com.feng.service.impl;

import com.feng.enetity.Student;

import com.feng.mapper.StudentMapper;

import com.feng.service.IStudentService;

public class StudentServiceImpl implements IStudentService {

    private StudentMapper studentMapper;

    public void setStudentMapper(StudentMapper studentMapper) {

        this.studentMapper = studentMapper;

    }

    @Override

    public void addStudent(Student student) {

        // 调用Dao

        studentMapper.addStudent(student);

    }

}

3、数据库配置db.properties

driver=com.mysql.cj.jdbc.Driver

url=jdbc:mysql://localhost:3306/xiao?serverTimezone=GMT%2B8

username=root

password=123456

4、测试

1、Test

package com.feng.test;

import com.feng.enetity.Student;

import com.feng.service.IStudentService;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

    public static void main(String[] args) {

        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        IStudentService studentService = (IStudentService)context.getBean("studentService");

        Student student = new Student();

        student.setStuNo(4);

        student.setStuAge(81);

        student.setStuName("xiaofeng1");

        studentService.addStudent(student);

    }

}

5、总结

借助Spring相关的jar包、极大的简化了Mybatis的操作、为后续的开发简便了很多步骤。

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