今晚继续复习mybtis
以根据id值查询单条数据为例
编写SqlMapConfig.xml文件

编写失血模型对象：Product,最好字段名和数据库里面的字段名一直

/**** Title: Product
* 【mybatis实现mapper代理模式的方式】Description: 商品类失血模型
* @author Alon *@date 2020年9月27日 下午6:51:57 * @version 1.0 */ public class Product {private int p_id; private String name; private int p_number; private double price; private String add_time; public Product(int p_id, String name, int p_number, double price, String add_time) { super(); this.p_id = p_id; this.name = name; this.p_number = p_number; this.price = price; this.add_time = add_time; }public Product() { super(); }public int getP_id() { return p_id; }public void setP_id(int p_id) { this.p_id = p_id; }public String getName() { return name; }public void setName(String name) { this.name = name; }public int getP_number() { return p_number; }public void setP_number(int p_number) { this.p_number = p_number; }public double getPrice() { return price; }public void setPrice(double price) { this.price = price; }public String getAdd_time() { return add_time; }public void setAdd_time(String add_time) { this.add_time = add_time; }@Override public String toString() { return "Product [p_id=" + p_id + ", name=" + name + ", p_number=" + p_number + ", price=" + price + ", add_time=" + add_time + "]"; } }

编写单个映射关系的sql.xml：product.xml

SELECT * FROM t_product WHERE p_id = #{value}

编写java代码进行测试执行sql语句并得到结果

/**** Title: MybatisDemo1
* Description: 查询数据的demo
*@author Alon * @date 2020年9月27日 下午7:05:32 * * @version 1.0 */ * public class MybatisDemo1 {*public static void main(String[] args) throws IOException { * new MybatisDemo1().queryById(); }* public void queryById() throws IOException {*//1、读取到SqlMapConfig.xml文件的流 String path = "SqlMapConfig.xml"; * InputStream config = Resources.getResourceAsStream(path); //创建会话工厂,同时将SqlMapConfig.xml里面的数据放到工厂中 SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(config); //开启会话 SqlSession sqlSession = factory.openSession(); /** 第一个参数：要执行哪个sql语句的参数，一般命名空间.id值 * 第二个参数：传入填充#{value}的传入参数值。 */ Object obj = sqlSession.selectOne("test.findById", 1); System.out.println(obj); } }

进行模糊查询：查询出多条结果集

SELECT * FROM t_product WHERE name like "%${value}%"public void queryByName() throws Exception{ String path = "SqlMapConfig.xml"; //获取流对象 InputStream config = Resources.getResourceAsStream(path); //获取会话工厂 SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(config); //开启会话 SqlSession sqlSession = factory.openSession(); /** 因为执行结果有多条语句，那么必须使用selectList */ List