Mybatis搭建流程

Mybatis搭建流程

1、引pom

		<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.17</version>
        </dependency>
        
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.3.0</version>
        </dependency>

2、写配置

<?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>
    <!--环境配置，连接的数据库，这里使用的是MySQL-->
    <environments default="mysql">
        <environment id="mysql">
            <!--指定事务管理的类型，这里简单使用Java的JDBC的提交和回滚设置-->
            <transactionManager type="JDBC"></transactionManager>
            <!--dataSource 指连接源配置，POOLED是JDBC连接对象的数据源连接池的实现-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"></property>
<!--                ?serverTimezone=UTC & ampcharacterEncoding=utf-8-->
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis_analysis?serverTimezone=UTC &amp; ampcharacterEncoding=utf-8"></property>
                <property name="username" value="root"></property>
                <property name="password" value="123456rw"></property>
            </dataSource>
        </environment>
    </environments>
    <!--这是告诉Mybatis区哪找持久化类的映射文件，对于在src下的文件直接写文件名，            如果在某包下，则要写明路径,如：com/mybatistest/config/User.xml-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"></mapper>
    </mappers>
<!--    两种方式去配置Mapper-->
</configuration>

3、建实体类

package com.mybatis.entity;

public class User {
    private Integer id;
    private String username;
    private String password;

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

4、建立Mapper和对应的XML

package com.mybatis.mapper;

import com.mybatis.entity.User;

import java.util.List;

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

XML

<?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.mybatis.mapper.UserMapper">

    <select id="selectAllUser" resultType="com.mybatis.entity.User">
        select * from user
    </select>


</mapper>

5、测试类

package com.mybatis;


import com.mybatis.entity.User;
import com.mybatis.mapper.UserMapper;
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.Reader;
import java.util.List;

public class Test {
    public static void main(String[] args) {
        try {
            //1、定义Mybatis文件
            String resource = "mybatis_config.xml";
            //2、IO操作 使用java的api读取配置文件获取InputStreamReader
            Reader resourceAsReader = Resources.getResourceAsReader(resource);
            //3、获取SQLSessionFactoryBuilder
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsReader);
            //4、通过获取SQLSessionFactoryBuilder获取session
            SqlSession sqlSession = sqlSessionFactory.openSession();
            //5、通过SqlSession去操作Mapper
        
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //6、执行SQL语句
            List<User> users = mapper.selectAllUser();
            for (User user : users) {
                System.out.println(user.toString());
            }
        } catch (IOException e) {


            e.printStackTrace();
        }
    }
}