mybatis快速入门

2.2Maven仓库

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.7</version>
</dependency>

<dependencies>
    <!--dependency>
      <groupId>org.wyl</groupId>
      <artifactId>[the artifact id of the block to be mounted]</artifactId>
      <version>1.0-SNAPSHOT</version>
    </dependency-->
    <!-- mysql驱动 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.18</version>
    </dependency>
    <!-- mybatis -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.5</version>
    </dependency>
    <!-- 整合log4j -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.6.4</version>
    </dependency>
      <!-- 测试junit -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

右击pom.xml->meave 重新加载项目。包下载完即可。

将 mybatis-x.x.x.jar 文件置于 classpath 中即可。

3.2.2.全局配置文件 mybatis-config

<?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标签 => 声明MyBatis核心配置 -->
<configuration>
    <!-- environments标签 => 设置MyBatis选用的环境信息 -->
    <environments default="development">
        <environment id="development">
            <!-- transactionManager标签 => 事务管理 -->
            <transactionManager type="JDBC"/>
            <!-- dataSource标签 => 配置数据源属性 -->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--将mapper映射文件注册到全局配置文件中-->
    <mappers>
        <mapper resource="org/mybatis/example/WylMapper.xml"/>
    </mappers>
</configuration>

<?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标签 => 声明MyBatis核心配置 -->
<configuration>
    <!-- environments标签 => 设置MyBatis选用的环境信息 -->
    <environments default="development">
        <environment id="development">
            <!-- transactionManager标签 => 事务管理 -->
            <transactionManager type="JDBC"/>
            <!-- dataSource标签 => 配置数据源属性 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url"
                          value="jdbc:mysql://localhost:3306/wyl?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf8&amp;serverTimezone=CST"/>
                <property name="username" value="nps"/>
                <property name="password" value="123.nps@zst"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="mappers/userMapper.xml"/>
    </mappers>

</configuration>

3.2.3.SqlSessionFactory 会话工厂

通过Mybatis的配置信息，使用 SqlSessionFactoryBuilder构建器，来构建会话工厂对象
SqlSessionFactory 创建了 Configuration对象，使用 Configuration对象来构建SqlSession会话工厂
SqlSessionFactoryBuilder构建器使用了 Builder构建者设计模式
SqlSessionFactory 会话工厂，使用了工厂设计模式

public class MyBatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        try {
            // 定义XML核心配置文件路径信息
            String resource = "mybatis-config.xml";
            // 读取XML核心配置文件路径信息
            InputStream inputStream = Resources.getResourceAsStream(resource);
            // 获得实例化SQLSessionFactory
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //调用SqlSessionFactory.openSession()方法，返回SqlSession对象
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}