mybatis环境搭建

1.使用工具

IDEA，MySQL数据库，maven

2.开始搭建

2.1数据表的创建

CREATE TABLE `user`(
`id` INT(20) NOT NULL PRIMARY KEY,
`name` VARCHAR(30) DEFAULT NULL,
`password` VARCHAR(30) DEFAULT NULL
)ENGINE=INNODB DEFAULT CHARSET=utf8;

2.2依赖的导入

需要导入的依赖有

  <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.mysql/mysql-connector-j -->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <version>8.0.31</version>
        </dependency>
    </dependencies>

2.3核心配置文件的编写（mybatis-config.xml）

<?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>
    <properties resource="db.properties"/>
    <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=GMT"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

2.4对应实体类的创建

public class User {
    private int id;
    private String name;
    private String password;
//此处省略get和set方法以及构造方法和toString方法
}

这里有一个注意点就是对象的属性名和数据库的列名要保持一致。

2.5工具类的编写

package com.fan.utils;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

public class MybatisUtil {
    public 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();
        }
    }
    public static SqlSession getSqlSession(){
        SqlSession sqlSession = sqlSessionFactory.openSession();

        return sqlSession;
    }


}

2.6Dao层代码的编写

Dao层的接口（UserMapper.java）：

package com.fan.dao;

import com.fan.pojo.User;

import java.util.List;

public interface UserMapper {
    //查询所有用户
    List<User> getUserList();
}

Dao层的xml文件（UserMapper.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.fan.dao.UserMapper">
    <select id="getUserList" resultType="com.fan.pojo.User">
        select * from mybatis.user;
    </select>
</mapper>

在核心配置文件中注册mapper

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

解决静态资源导出问题：在pom.xml文件中加入以下代码:

    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

2.7测试

    @Test
    public void test(){
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.getUserList();
        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }


>  以上就是mybatis的环境搭建的整个过程了。