Spring 整合MyBatis

2024-02-11 18:08:16

Spring 整合MyBatis

1.在pom.xml中导入依赖包

导入依赖包后，会自动下载，如果代码一直是红的刷新Maven就行了

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.13.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.13.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
    </dependencies>

    <!--配置Maven静态资源过滤问题！-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering><!--防止application.xml被过滤-->
            </resource>
        </resources>
    </build>

先给出完成后的Maven目录，以下建文件的步骤可以参照这个

2.类及接口，Mapper映射文件

编写pojo实体类 User.java

package com.kuang.pojo;

public class User {
    //这里属性对应自己数据库user表里的字段，id，name姓名，pwd密码
    private int id;
    private String name;
    private String pwd;

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

UserMapper接口编写

package com.kuang.mapper;

import com.kuang.pojo.User;
import java.util.List;

public interface UserMapper {
    public List<User> selectUser();
}

先创建mybatis的创建文件，里面可以配置别名等功能
mybatis-config.xml

<?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>
<!--设置别名，UserMapper.xml的返回值resultType="User"就行了
	不用写全路径-->
   <typeAliases>
       <package name="com.kuang.pojo"/>
   </typeAliases>
   
<!--这里省略，数据源会在Spring的配置文件中配置
   <environments default="development">
       <environment id="development">
           <transactionManager type="JDBC"/>
           <dataSource type="POOLED">
               <property name="driver" value="com.mysql.jdbc.Driver"/>
               <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
               <property name="username" value="root"/>
               <property name="password" value="123456"/>
           </dataSource>
       </environment>
   </environments>
-->
</configuration>

接口对应的Mapper映射文件
UserMapper.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.kuang.mapper.UserMapper">

   <select id="selectUser" resultType="User">
    select * from user
   </select>

</mapper>

3.引入Spring配置文件spring-config.xml

重点来了，Spring配置文件：spring-config.xml
里面<bean id=“sqlSessionFactory” 里可以引用mybatis-config.xml跟Mapper.xml文件
spring-config.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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--DataSource: 使用Spring的数据源替换Mybatis的配置，这里使用Spring提供的JDBC
    	注意：数据源导入自己数据库信息-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;useEncode=true&amp;characterEncode=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value="123"/>
    </bean>

    <!--配置sqlSessionFactory，关联MyBatis-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/kuang/mapper/*.xml"/>
    </bean>
    <!--就是我们使用的sqlSession，注册sqlSessionTemplate，关联sqlSessionFactory-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能用构造器注入sqlSessionFactory，因为它没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

</beans>

4.增加接口的实现类

增加UserMapper接口的实现类，私有化sqlSessionTemplate
UserMapperImpl.java

package com.kuang.mapper;

import com.kuang.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;

public class UserMapperImpl implements UserMapper {

    //sqlSession不用我们自己创建了，Spring来管理
    private SqlSessionTemplate sqlSession;

    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }

    public List<User> selectUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUser();
    }

}

5.注册bean实现

创建一个新的applicationContext.xml，import标签导入spring-config.xml，再编写bean的实现
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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <import resource="spring-config.xml"/>

    <!--把实现类UserMapperImpl 注入到容器bean中，sqlSession是参数-->
    <bean id="userMapper" class="com.kuang.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>

</beans>

6.测试

MyTest.java

import com.kuang.mapper.UserMapper;
import com.kuang.pojo.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    @Test
    public void test(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper",UserMapper.class);
        for (User user : userMapper.selectUser()) {
            System.out.println(user);
        }
    }
}

连接数据库，打开数据库中的表

运行结果就是打印数据库user表中的数据

上述步骤亲测可运行，以上案例参考了狂神老师微信公众号狂神说上面的文章笔记

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