MyBatis-01:环境搭建

1.搭建实验数据库

CREATE DATABASE `mybatis`;

USE `mybatis`;

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (

`id` int(20) NOT NULL,

`name` varchar(30) DEFAULT NULL,

`pwd` varchar(30) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

insert  into `user`(`id`,`name`,`pwd`) values (1,'狂神','123456'),(2,'张三','abcdef'),(3,'李四','987654');

2.导入 Maven 相关依赖

<dependency>

   <groupId>org.mybatis</groupId>

   <artifactId>mybatis</artifactId>

   <version>3.5.2</version>

</dependency>

<dependency>

   <groupId>mysql</groupId>

   <artifactId>mysql-connector-java</artifactId>

   <version>5.1.47</version>

</dependency>

3.编写 MyBatis 核心配置文件

可以根据帮助文档来进行编写

<?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>

   <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?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>

               <property name="username" value="root"/>

               <property name="password" value="123456"/>

           </dataSource>

       </environment>

   </environments>

   <mappers>

       <mapper resource="com/kuang/dao/userMapper.xml"/>

   </mappers>

</configuration>

4.编写 MyBatis 工具类

import org.apache.ibatis.io.Resources;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;

import java.io.InputStream;

public class MybatisUtils {

   private static SqlSessionFactory sqlSessionFactory;

   static {

       try {

           String resource = "mybatis-config.xml";

           InputStream inputStream = Resources.getResourceAsStream(resource);

           sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

      } catch (IOException e) {

           e.printStackTrace();

      }

  }

   //获取SqlSession连接

   public static SqlSession getSession(){

       return sqlSessionFactory.openSession();

  }

}

5.创建实体类

public class User {

   private int id;  //id

   private String name;   //姓名

   private String pwd;   //密码

   //构造,有参,无参

   //set/get

   //toString()

}

6.编写 Mapper 接口

import com.kuang.pojo.User;

import java.util.List;

public interface UserMapper {

   List<User> selectUser();

}

7.编写 Mapper.xml 配置文件

注意 namespace 不要写错！

<?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">

<mapper namespace="com.kuang.dao.UserMapper">

 <select id="selectUser" resultType="com.kuang.pojo.User">

  select * from user

 </select>

</mapper>

8.编写测试类

Junit 包测试

public class MyTest {

   @Test

   public void selectUser() {

       SqlSession session = MybatisUtils.getSession();

       //方法一:

       //List<User> users = session.selectList("com.kuang.mapper.UserMapper.selectUser");

       //方法二:

       UserMapper mapper = session.getMapper(UserMapper.class);

       List<User> users = mapper.selectUser();

       for (User user: users){

           System.out.println(user);

      }

       session.close();

  }

}

9.运行结果

出现的问题:

1、Maven 静态资源过滤问题

<resources>

   <resource>

       <directory>src/main/java</directory>

       <includes>

           <include>**/*.properties</include>

           <include>**/*.xml</include>

       </includes>

       <filtering>false</filtering>

   </resource>

   <resource>

       <directory>src/main/resources</directory>

       <includes>

           <include>**/*.properties</include>

           <include>**/*.xml</include>

       </includes>

       <filtering>false</filtering>

   </resource>

</resources>

巴特西

MyBatis-01:环境搭建

MyBatis-01:环境搭建

1.搭建实验数据库

2.导入 Maven 相关依赖

3.编写 MyBatis 核心配置文件

4.编写 MyBatis 工具类

5.创建实体类

6.编写 Mapper 接口

7.编写 Mapper.xml 配置文件

8.编写测试类

9.运行结果

出现的问题:

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