思路　搭建环境->导入myBatis->编写代码-》测试

1.搭建环境

• 搭建数据库

CREATE DATABASE ’mybatis‘

USE ‘mybatis’

CREATE TABLE USER(
id INT(20) NOT NULL PRIMARY KEY ,
name VARCHAR(30) DEFAULT(NULL),
pwd VARCHAR(30) DEFAULT(NULL)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO user(id,name,pwd)VALUES
(1,'狂神','123456'),
(2,'张三','123'),
(3,'李四','123')

•  新建项目

　　　　1.新建maven新项目

　　　　2.删除src目录

　　　　3.导入maven依赖

• 创建一个模块

1.编写mybatis核心配置文件

2.编写mybatis工具类

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
static {

    try {
        //使用mybatis第一步获取slqSession对象
        String resource = "mybatis-config.xml";
        InputStream     inputStream = Resources.getResourceAsStream(resource);
         sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }

}

//既然有了 SqlSessionFactory，顾名思义，我们可以从中获得 SqlSession 的实例
    //SqlSession 提供了在数据库执行 SQL 命令所需的所有方法
    public static SqlSession getSqlsession(){

        SqlSession sqlSession = sqlSessionFactory.openSession();
        return sqlSession ;
    }

}

• 编写代码

  • 实体类

    public class User {
        private int id;
        private String name ;
        private String pwd;
    
        public User() {
        }
    
        public User(int id, String name, String pwd) {
            this.id = id;
            this.name = name;
            this.pwd = pwd;
        }
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getPwd() {
            return pwd;
        }
    
        public void setPwd(String pwd) {
            this.pwd = pwd;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", pwd='" + pwd + '\'' +
                    '}';
        }
    }

  • dao接口

    public interface UserDao { List <User> getUserList(); }

     

  • 接口实现类由原来的impl转换为一个mapper文件

    <?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">
    <!--namespace绑定一个对应的dao接口或这mapper接口-->
    <mapper namespace="dao.UserDao">
    <!--    select查询语句-->
        <select id="getUserList" resultType="pojo.User">
            select * from mybatis.user
        </select>
    </mapper>
    
    

     

• 测试

  • 注意点

　　　　　　　　org.apache.ibatis.binding.BindingException: Type interface dao.UserDao is not known to the MapperRegistry.

MapperRegistry

每一个都要注册

 <mappers>
        <mapper resource="dao.UserMapper.xml"/>
    </mappers>

开启资源过滤

 <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>

• • junit测试