MyBatis框架快速入門

//1.導入maven依賴
	需要導入的有 mybatis ,mysql,log4j(日誌),Junit(測試)

  
  //2.創建數據庫user表   創建實體類USer
      
  //3.創建接口UserDao.java
      public interface UserDao{
      //查詢所有
      	List<User> findAll();
    }

4.在maven的resources目錄下創建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>
    <!--關聯數據庫的信息-->
    <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_db"/>
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--關聯保存sql語句的配置文件-->
        <mapper resource="cn/itcast/dao/UserDao.xml"/>
    </mappers>
</configuration>

5.在resources目錄下創建和dao一樣的目錄結構,在dao中創建保存sql語句的UserDao.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">
<!--namespace 要求是 dao接口類的全路徑-->
<mapper namespace="cn.itcast.dao.UserDao">
    <!--
        id : 是當前sql語句的唯一標識, 寫成方法名
        resultType : 將結果封裝到指定的類型中
    -->
    <select id="queryAll" resultType="cn.itcast.domain.User">
        select * from user;
    </select>
</mapper>

6.測試

public class UserDaoTest {
    @Test
    public void queryAll() throws Exception {
        //1.讀取配置文件
        InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
      	// 2 根據配置文件創建工廠類
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        // 3 從工廠類獲取 執行sql的對象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        // 4 執行sql 獲得結果 處理結果
        List<User> userList = sqlSession.selectList("cn.itcast.dao.UserDao.queryAll");
        for (User user : userList) {
            System.out.println(user);
        }
        // 5 釋放資源
        sqlSession.close();
        in.close();
    }

}