Mybatis的使用

ORMapping: Object Relationship Mapping 对象关系映射

对象指⾯向对象

关系指关系型数据库

Java 到 MySQL 的映射，开发者可以以⾯向对象的思想来管理数据库。

如何使⽤

• 新建 Maven ⼯程，pom.xml

<dependencies>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.5</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.11</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.6</version>
        <scope>provided</scope>
    </dependency>
</dependencies>
<build>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.xml</include>
            </includes>
        </resource>
    </resources>
</build>

• 新建数据表

use mybatis;
create table t_account(
id int primary key auto_increment,
username varchar(11),
password varchar(11),
age int
)

• 新建数据表对应的实体类 Account

package com.southwind.entity;

import lombok.Data;

@Data
@AllArgsConstructor
public class Account {

private long id;

private String username;

private String password;

private int age;

}

• ⾃定义接⼝

package com.southwind.mapper;

import com.southwind.entity.Account;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

@Mapper
public interface AccoutMapper {
    Account save(@Param("username")String username,@Param("password")String password,@Param("age")int age);
}

• mapper.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.southwind.mapper.AccoutMapper">
    <insert id="save" parameterType="com.southwind.entity.Account">
        insert into t_account(username, password, age)
        values (#{username},#{password}, #{age})
    </insert>
</mapper>

• 创建 MyBatis 的配置⽂件 confifig.xml，⽂件名可⾃定义

<?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>
    <!-- 配置MyBatis运⾏环境 -->
    <environments default="development">
        <environment id="development">
            <!-- 配置JDBC事务管理 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- POOLED配置JDBC数据源连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"></property>
                <property name="url"
                          value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"></property>
                <property name="username" value="root"></property>
                <property name="password" value="123456"></property>
            </dataSource>
        </environment>
    </environments>

    <!-- 注册AccountMapper.xml -->
    <mappers>
        <mapper resource="com/southwind/mapper/AccountMapper.xml"></mapper>
    </mappers>
</configuration>

• 测试

package com.southwind.entity;

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

import java.io.InputStream;

public class Test {
    public static void main(String[] args) {
        //加载MyBatis配置⽂件
        InputStream inputStream =
                Test.class.getClassLoader().getResourceAsStream("config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new
                SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory =
                sqlSessionFactoryBuilder.build(inputStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        String statement = "com.southwind.mapper.AccoutMapper.save";
        Account account = new Account(1L, "张三", "123123", 22);
        sqlSession.insert(statement, account);
        sqlSession.commit();
    }
}

运行结果，成功插入