[大数据]mybatis使用步骤

1.在该项目中的pom.xml，添加相关依赖，导入相关jar包

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

2.在resources中建一个mybatis-config.xml配置文件，连接相关数据库语句

<environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/bb?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>

3.编写实体类
4.编写相关接口userMapper.java、以及UserMapper.xml

<mapper namespace="dao.UserMapper"><!-- 对应的接口-->
    <select id="getUserByLimit" parameterType="map" resultType="user"> 
        select  * from product limit #{startindex},#{pagesize}
    </select>

id为该方法的名字，paramaterType为传递参数的属性，resultType为返回类型
5.编写测试类
``mybatis是通过sqlSessionFactory–>Sqlsession–>执行sql语句

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
   static  {
        try {//获取sqlsessionFactory对象
            String resource = "mybatis-config.xml";
           InputStream inputStream = Resources.getResourceAsStream(resource);
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  public static SqlSession getSqlSession(){
      SqlSession sqlSession = sqlSessionFactory.openSession();
        return sqlSession;
  }

---------
SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> userlist = userMapper.getUserlist();