思路：搭建环境--->导入Mybatis--->编写代码--->测试

1.1、搭建环境

搭建数据库

create databases if not exists `mybatis`;use `mybatis`;create table if not exists `user`(    `id` int(20) not null,    `name` varchar(30) default null,    `pwd` varchar(30) default null,    primary key(`id`))engine=innodb default charset=utf8;

插入数据

insert into `user`(`id`,`name`,`pwd`) values(1,'孙悟空','123456'),(2,'猪八戒','111222'),(3,'唐僧','789456');

新建我的项目
1.新建一个一般的maven我的项目
2.删除src目录
3.导入maven依赖

<dependencies>    <!--mysql驱动-->    <dependency>        <groupId>mysql</groupId>        <artifactId>mysql-connector-java</artifactId>        <version>5.1.46</version>    </dependency>        <!--mybatis-->    <dependency>        <groupId>org.mybatis</groupId>        <artifactId>mybatis</artifactId>        <version>3.5.2</version>    </dependency>        <!--junit-->    <dependency>        <groupId>junit</groupId>        <artifactId>junit</artifactId>        <version>4.12</version>    </dependency></dependencies><!--在build中配置resources，来避免咱们资源导出失败的问题--><build>    <resources>        <resource>            <directory>src/main/java</directory>            <includes>                <include>**/*.properties</include>                <include>**/*.xml</include>            </includes>            <filtering>true</filtering>        </resource>        <resource>            <directory>src/main/resources</directory>            <includes>                <include>**/*.properties</include>                <include>**/*.xml</include>            </includes>            <filtering>true</filtering>        </resource>    </resources></build>

1.2、创立一个模块

• 编写Mybaris的外围配置文件

  <?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><!--configuration外围配置文件--><configuration><environments default="development">  <environment id="development">    <transactionManager type="JDBC"/>    <dataSource type="POOLED">      <property name="driver" value="com.mysql.cj.jdbc.Driver"/>      <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8&amp;serverTimezone=Asia/Shanghai"/>      <property name="username" value="root"/>      <property name="password" value="root"/>    </dataSource>  </environment></environments><mappers>  <mapper resource="com/jialidun/dao/UserMapper/xml"/></mappers></configuration>

• 编写mybatis工具类

  package com.jialidun.utils;//sqlSessionFactory--->sqlSessionpublic class MybatisUtils{  private static SqlSessionFactory sqlSessionFactory;  static{  try{      //应用mybatis第一步：获取sqlSessionFactory对象      String resource = "mybatis-config.xml";      InputStream inputStream = Resources.getResourceAsStream(resource);      sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);      }catch(IOException e){          e.printStackTrace();      }  }//既然有了 SqlSessionFactory，顾名思义，咱们能够从中取得 SqlSession 的实例。//SqlSession 提供了在数据库执行 SQL 命令所需的所有办法。  public static SqlSession getSqlSession(){      return sqlSessionFactory.openSession();  }}

  1.3、编写代码

• 实体类

  package com.jialidun.pojo;@Datapublic class User{  private int id;  private String name;  private String pwd;}

• Dao接口

  package com.jialidun.dao;public interface UserDao{  List<User> getUserList();}

• 接口实现类由原来的UserDaoImpl转变为一个Mapper配置文件
  UserMapper.xml

  <?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><!--namespace=绑定一个对应的Dao/Mapper接口--><mapper namespace="com.jialidun.dao.UserDao"> <!--select查问语句--><select id="getUserList" resultType="com.jialidun.pojo.User">  select * from mybatis.user</select></mapper>

  1.4、测试

  留神点：
  org.apache.ibatis.binding.BindingException:Type interface com.jialidun.dao.UserDao is not know to the MapperRegistry.

  package com.jialidun.dao;public class UserDaoTest{  @Test  public void test(){            //第一步：取得SqlSession对象      SqlSession sqlSession = MybatisUtils.getSqlSession();            try{      UserDao userDao= sqlSession.getMapper(UserDao.class);      List<User> userList = userDao.getUserList();            //形式二：      //List<User> userList = sqlSession.selectList("com.jialidun.dao.UserDao.getUserList");      for(User user:userList){          System.out.println(user);      }      }catch(Exception e){          e.printStackTrace();      }finally{          //敞开SqlSession          sqlSession.close();      }          }}

  可能遇到的问题：
  1.配置文件没有注册
  2.绑定接口谬误
  3.办法名不对
  4.返回类型不对
  5.Maven导出资源问题