mybatis 注解入门案例

mybatis 注解入门

//用户持久层接口
public interface IUserDao {
    @Select("select * from User where id=41")
    List<User> findAll();
}

主配置文件

<?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>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql环境-->
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <!--配置链接数据库标准信息-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis01"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <!--使用注解时应该使用class来指定class属性的全限定类名-->
        <mapper class="com.ljq.dao.IUserDao"/>
    </mappers>
</configuration>

测试类

public class MybatisTest {
    //入门案例
    public static void main(String[] args) throws IOException {
        //1.读取配置文件
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.使用工厂生产SqlSession对象
        SqlSession session = factory.openSession();
        //4.使用SqlSessiion创建Dao接口的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);
        //5.使用代理对象执行方法
        List<User> users = userDao.findAll();
        for (User user:users){
            System.out.println(user);
        }
        //6.释放资源
        session.close();
        in.close();

    }
}