1.先写一个数据源的工具类

package com.sunshine.util;
​
import org.springframework.jdbc.datasource.DriverManagerDataSource;
​
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
​
public class SessionFactory {
​
    DataSource dataSource;
    public SessionFactory(){
        //创建连接池
        DriverManagerDataSource source = new DriverManagerDataSource();
        source.setDriverClassName("com.mysql.jdbc.Driver");
        //账号和密码
        source.setUsername("root");
        source.setPassword("root");
        //所要查数据库
        source.setUrl("jdbc:mysql://localhost:3306/mydb1?serverTimezone=Asia/Shanghai");
        dataSource=source;
    }
​
    //创建连接的办法
    public Session createSession(){
        Connection connection = null;
        try {
           connection = dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        return  new Session(connection);
    }
​
}

2.在写一个将resultSet转为List的工具类

package com.sunshine.util;
​
import lombok.extern.slf4j.Slf4j;
​
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.*;
​
@Slf4j(topic = "e")
public class ResultSetUtil {
    public static List<Map> resultSetToList(ResultSet rs) throws java.sql.SQLException {
        if (rs == null)
            return Collections.EMPTY_LIST;
        ResultSetMetaData md = rs.getMetaData(); //得到结果集(rs)的结构信息，比如字段数、字段名等
        int columnCount = md.getColumnCount(); //返回此 ResultSet 对象中的列数
        List<Map> list = new ArrayList<Map>();
        Map rowData = new HashMap();
        while (rs.next()) {
            rowData = new HashMap(columnCount);
            for (int i = 1; i <= columnCount; i++) {
                rowData.put(md.getColumnName(i).toLowerCase(), rs.getObject(i));
            }
            list.add(rowData);
            log.debug("list:"+list.toString());
​
        }
        return list;
    }
}

3.在写一个测试类TestMybatis

package com.sunshine.test;
​
import com.sunshine.session.Session;
import com.sunshine.util.ResultSetUtil;
import com.sunshine.util.SessionFactory;
import lombok.extern.slf4j.Slf4j;
​
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
​
@Slf4j(topic = "e")
public class TestMybatis {
    public static void main(String[] args) {
        try {
            String sql = "select * from emp";
             //获得Session对象
            Session session = new SessionFactory().createSession();
             //通过Session对象获得连接对象
            Connection connection =session.getConnection();
            //进行预编译
             PreparedStatement psmt = connection.prepareStatement(sql);
            ResultSet res = psmt.executeQuery();
            //调用方法将resultSet转为List
            List list = ResultSetUtil.resultSetToList(res);
            
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}