MyBatis Source - Mybatis 基础使用 - 《Java 知识总结 Knowledge Summary

1.原生Api使用
2.Mybatis联合Spring使用

Sql建表语句

CREATE TABLE `user` (
    `age` int(11) NOT NULL,
    `name` varchar(64) NOT NULL DEFAULT '',
    `id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

1.原生Api使用

测试用例

package cn.shiyujun.mybatis;
import cn.shiyujun.entity.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
/**
 * @author jsf
 * @description:
 * @date 1/4/2021 10:03 AM
 */
public class TestMyBatis {
    static SqlSessionFactory sqlSessionFactory = null;
    static {
        sqlSessionFactory = MyBatisUtil.getSqlSessionFactory();
    }
    public static void main(String[] args) {
        testAdd();
        getUser();
    }
    public static void testAdd() {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        try {
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            User user = new User(1, "lisi", new Integer(25));
            userMapper.insertUser(user);
            User user2 = new User(2, "zhangsan", new Integer(25));
            userMapper.insertUser(user2);
            sqlSession.commit();// 这里一定要提交，不然数据进不去数据库中
        } finally {
            sqlSession.close();
        }
    }
    public static void getUser() {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        try {
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            User user = userMapper.getUser("zhangsan");
            System.out.println("name: " + user.getName() + "|age: "
                    + user.getAge());
        } finally {
            sqlSession.close();
        }
    }
}

工具类

public class MyBatisUtil {
    private final static SqlSessionFactory sqlSessionFactory;
    static {
        String resource = "mybatis-config.xml";
        Reader reader = null;
        try {
            reader = Resources.getResourceAsReader(resource);
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
    }
    public static SqlSessionFactory getSqlSessionFactory() {
        return sqlSessionFactory;
    }
}

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>
    <!-- 加载类路径下的属性文件 -->
    <properties resource="db.properties">
    </properties>
    <settings>
        <!-- changes from the defaults for testing -->
        <setting name="cacheEnabled" value="false" />
        <setting name="useGeneratedKeys" value="true" />
        <setting name="defaultExecutorType" value="REUSE" />
    </settings>
    <!-- 设置实体类的类型别名 -->
    <typeAliases>
        <typeAlias type="cn.shiyujun.entity.User" alias="user"/>
    </typeAliases>
    <!-- 设置一个默认的连接环境信息，支持多数据源 -->
    <environments default="mysql_env">
        <!-- 连接环境信息，取一个唯一的编号 -->
        <environment id="mysql_env">
            <!-- mybatis使用的jdbc事务管理方式 -->
            <transactionManager type="jdbc">
            </transactionManager>
            <!-- mybatis使用连接池方式来获取链接 -->
            <dataSource type="pooled">
                <!-- 配置与数据库交互的四个属性 -->
                <property name="driver" value="${mysql.driver}"/>
                <property name="url" value="${mysql.url}"/>
                <property name="username" value="${mysql.username}"/>
                <property name="password" value="${mysql.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mappers/UserMapper.xml"/>
    </mappers>
</configuration>

db.properties

mysql.driver=com.mysql.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&useSSL=false
mysql.username=root
mysql.password=root

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">
<!-- 名称空间namespace必须唯一 -->
<mapper namespace="cn.shiyujun.mybatis.UserMapper">
    <!-- 这里namespace必须是UserMapper接口的路径” -->
    <insert id="insertUser" parameterType="User">
        insert into user(id,name,age) values(#{id},#{name},#{age})
        <!-- 这里sql结尾不能加分号，否则报“ORA-00911”的错误 -->
    </insert>
    <!-- 这里的id必须和UserMapper接口中的接口方法名相同 -->
    <select id="getUser" resultType="User" parameterType="java.lang.String">
        select * from user where name=#{name}
    </select>
</mapper>

UserMapper

public interface UserMapper {
    public void insertUser(User user);
    public User getUser(String name);
}

2.Mybatis联合Spring使用

测试用例

public class TestSpringMybatis {
    public static void main(String[] args) {
        testMapper();
        testMapperFactoryBeanMapper();
    }
    public static void testMapper(){
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:application-mybatis.xml");
        //<mybatis:scan> 注入的mapper
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        User user = userMapper.getUser("zhangsan");
        System.out.println("name: " + user.getName() + "|age: " + user.getAge());
    }
    public static void testMapperFactoryBeanMapper(){
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:application-mybatis.xml");
        //MapperFactoryBean 注入的mapper, 获取工厂本事用name &userMapper2
        UserMapper userMapper = context.getBean("userMapper2", UserMapper.class);
        User user = userMapper.getUser("zhangsan");
        System.out.println("name: " + user.getName() + "|age: " + user.getAge());
    }
}

db.properties、mybatis-config.xml、UserMapper.java、UsreMapper.xml 均和上方一致

application-mybatis.xml

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mybatis="http://mybatis.org/schema/mybatis-spring"
       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://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring.xsd"
       default-autowire="byName">
    <!-- 加载属性资源 -->
    <context:property-placeholder location="classpath:/db.properties"></context:property-placeholder>
    <!-- 配置 SqlSessionFactoryBean  -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- mybatis 配置文件位置（默认配置的话，可以不用）-->
        <property name="configLocation" value="classpath:/mybatis-config.xml"></property>
        <!-- 配置映射器文件（mybatis-config 中已经配置了） -->
        <!--        <property name="mapperLocations" value="classpath:/mappers/UserMapper.xml" />-->
    </bean>
    <!-- 配置数据源 -->
    <!-- 这里使用的是 druid 连接池，需要另外导入 druid.jar -->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <property name="driverClassName" value="${mysql.driver}" />
        <property name="url" value="${mysql.url}" />
        <property name="username" value="${mysql.username}" />
        <property name="password" value="${mysql.password}" />
    </bean>
    <!-- 事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    <!-- SqlSessionTemplate管理mybatis的qlSession,线程安全,可以被多个DAO所共享使用 -->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory" />
        <!-- 配置了BATCH 表示所有的语句可以批量操作 -->
        <constructor-arg index="1" value="BATCH" />
    </bean>
    <!-- mapper扫描后注入spring容器   -->
    <mybatis:scan base-package="cn.shiyujun.mybatis" />
    <!--     MapperFactoryBean继承了SqlSessionDaoSupport   -->
    <bean id="userMapper2" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="cn.shiyujun.mybatis.UserMapper" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean>
</beans>