spring——maven项目中spring整合mybatis

mybatis-spring目录

• Ⅰ、jar包
• Ⅱ、创建spring配置文件、mybatis主配置文件、mybatis映射配置文件
• Ⅲ、附件

原理——spring整合mybatis就是动态代理拿到代理对象（sqlSession），使用代理对象通过dao层操作数据库，over！！！

目的——使用spring整合mybatis后，通过id查询school数据库中的student表中的字段，并打印在控制台。

注意——注意代码中的注释。

Ⅰ、jar包

pom.xml

 <dependencies>
     <!--引入spring核心容器.3个-->
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>5.1.7.RELEASE</version>
      </dependency>
      <!--mysql-->
      <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>8.0.15</version>
      </dependency>
      <!--mybatis-->
      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.5.2</version>
      </dependency>
      <!--spring整合mybatis-->
      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis-spring</artifactId>
          <version>2.0.2</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-jdbc</artifactId>
          <version>5.1.7.RELEASE</version>
      </dependency>
      <!--druid连接池-->
      <dependency>
          <groupId>com.alibaba</groupId>
          <artifactId>druid</artifactId>
          <version>1.1.16</version>
      </dependency>
      <!--spring-test-->
      <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.13</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-test</artifactId>
          <version>5.1.7.RELEASE</version>
      </dependency>
  </dependencies>

Ⅱ、创建spring配置文件、mybatis主配置文件、mybatis映射配置文件

一、spring配置文件 0

src/main/Recources/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"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop 
https://www.springframework.org/schema/aop/spring-aop.xsd 
http://www.springframework.org/schema/context 
https://www.springframework.org/schema/context/spring-context.xsd">

<!--spring整合mybatis必须要的-->
    <!--引入属性配置文件-->
    <context:property-placeholder location="classpath:db.properties"></context:property-placeholder>
    <!--初始化数据源-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${db.driver}"></property>
        <property name="url" value="${db.url}"></property>
        <property name="username" value="${db.username}"></property>
        <property name="password" value="${db.password}"></property>
    </bean>
    <!--spring整合mybatis，创建sqlSessionFactory-->
    <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--指定数据源-->
        <property name="dataSource" ref="dataSource"></property>
        <!--初始化mybatis主配置文件-->
        <property name="configLocation" value="classpath:mybatisConfig.xml"></property>
        <!--初始化mybatis映射配置文件-->
        <property name="mapperLocations" value="classpath:studentMapper.xml"></property>
        <!--批量取别名，可以写在mybatis主配置文件中-->
        <property name="typeAliasesPackage" value="com.hbw.bean"></property>
    </bean>


    <!--使用spring创建接口代理对象-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--注入sqlSessionFactory-->
        <!--sqlSession操作数据库，但是由sqlSessionFactory生产sqlSessionFactory-->
        <!--这里的sqlSessionFactoryBeanName是String类型，所以使用value属性，而不是ref-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryBean"></property>
        <!--扫描dao层下的所有接口-->
        <!--动态代理（目标代理对象操作数据库就是sqlSession），生产代理实例-->
        <property name="basePackage" value="com.hbw.dao"></property>
    </bean>

</beans>

二、mybatis主配置文件

src/main/Recources/mybatisConfig.xml
注意——这里虽然没写内容但是必须存在本来有些内容改在这里面写的，但是我写在spring配置文件中了

<?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>
<!--这里可以写很多配置：取别名、插件等-->
</configuration>

三、mybatis映射配置文件

src/main/Recources/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">
<mapper namespace="com.hbw.dao.StudentDao">
    <!--resultType是实体类全类名，但是我在spring中取别名了-->
    <select id="getStudentById" resultType="student">
        select sid,sname,sage,ssex,semail from student where sid=#{sid}
    </select>
</mapper>

Ⅲ、附件

一、实体类

src/main/java/com/hbw/bean/Student.java

package com.hbw.bean;

import java.io.Serializable;

public class Student implements Serializable {
    private int sid;
    private String sname;
    private int sage;
    private String ssex;
    private String semail;

    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public int getSage() {
        return sage;
    }

    public void setSage(int sage) {
        this.sage = sage;
    }

    public String getSsex() {
        return ssex;
    }

    public void setSsex(String ssex) {
        this.ssex = ssex;
    }

    public String getSemail() {
        return semail;
    }

    public void setSemail(String semail) {
        this.semail = semail;
    }

    @Override
    public String toString() {
        return "Student{" +
                "sid=" + sid +
                ", sname='" + sname + '\'' +
                ", sage=" + sage +
                ", ssex='" + ssex + '\'' +
                ", semail='" + semail + '\'' +
                '}';
    }
}

二、dao层接口

不需要手动创建dao层实例，自动创建

src/main/java/com/hbw/dao/StudentDao.java

package com.hbw.dao;

import com.hbw.bean.Student;
import org.springframework.stereotype.Repository;

@Repository
public interface StudentDao {
    Student getStudentById(int sid);
}

三、测试

src/test/java/StudentTest.java

import com.hbw.dao.StudentDao;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;


@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:applicationContext.xml"})
public class StudentTest {
    @Autowired
    private StudentDao studentDao;
    @Test
    public void test(){
        System.out.println(studentDao.getStudentById(17));
    }
}