MyBatis入门

搭建环境

1、 创建数据库

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, '张三','123456'),
(2, '李四','123456'),
(3, '王明','123456')

　　

2 新建项目--Maven项目

导入MyBatis相关jar包

pom.xml

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.47</version>
    </dependency>

    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.2</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>4.12</artifactId>
    </dependency>
</dependencies>

　　

创建一个模块 Maven

 

 

 

3 编写MyBatis核心配置文件

 

 

 

<?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&useUnicode=true&characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

　　

4 编写MyBatis工具类

 

 

 

//获取SqlSessionFactory对象
private static SqlSessionFactory sqlSessionFactory;
static {
     try {

         String resource = "mybatis-config.xml";
         InputStream inputStream = null;
         inputStream = Resources.getResourceAsStream(resource);
         sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
     } catch (IOException e) {
         e.printStackTrace();
     }
 }
 public static SqlSession getSqlSession(){
    return sqlSessionFactory.openSession();

 }

　

5 创建实体类

package com.bupt.pojo;

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 String getName() {
        return name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

　　

6 编写Mapper接口类

package com.bupt.dao;

import com.bupt.pojo.User;

import java.util.List;

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

　　

7编写Mapper.xml配置文件

<?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">
<mapper namespace="com.bupt.dao.UserMapper">
    <select id="getUserList" resultType="com.bupt.pojo.User">
    select * from mybatis.user
  </select>
</mapper>

　8　测试类

package com.bupt.dao;

import com.bupt.pojo.User;
import com.bupt.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserMapperTest {
    @Test
    public void test(){
        //获取 sqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = userMapper.getUserList();
        for(User user:users){
            System.out.println(user);
        }
        sqlSession.close();
    }

}

　　

　可能出现问题说明：Maven静态资源过滤问题

 

//pom.xml文件
<build>
        <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>
    </build>

　　完整目录

 参考资料：https://www.bilibili.com/video/BV1NE411Q7Nx?t=1545&p=2