MyBatis快速入门

最新推荐文章于 2025-06-29 21:42:43 发布

原创最新推荐文章于 2025-06-29 21:42:43 发布 · 523 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#mybatis

总结：

mybatis的简单执行流程：

1. 创建SqlSessionFactory

2. 从sqlSessionFactory中获取session

3. 在session中执行sql语句

4. 将获取结果映射

5. 关闭session

查询user表中所有数据

1. 创建user表，添加数据

create table tb_user (
    id int,
    last_name varchar(32),
    email varchar(32),
    gender varchar(8)
);

insert into tb_user(id, last_name, email, gender)
value (1,'李四','lisi@qq.com','男');


insert into tb_user(id, last_name, email, gender)
value (2,'张三','zhangsan@qq.com','男');

2. 创建模块，导入坐标

2.1 创建maven工程项目

使用idea创建一个maven工程项目

2.2 pom.xml导入依赖

<dependencies>
	<dependency>
		<groupId>org.mybatis</groupId>
		<artifactId>mybatis</artifactId>
		<version>3.5.16</version>
	</dependency>

	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
		<version>8.0.30</version>
	</dependency>
</dependencies>

3. 编写MyBatis核心配置文件

编写mybatis-config.xml配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://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.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis_1129"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="EmployeeMapper.xml"/>
    </mappers>
</configuration>

4. 编写SQL映射文件

编写sql映射文件

<?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="suibian">
    <select id="selectEmployee" resultType="com.atguigu.mybatis.helloworld.User">
        select id ,last_name lastName ,email ,gender from tb_user
    </select>
</mapper>

5. 编码

5.1 定义POJO类

package com.atguigu.mybatis.helloworld;

public class User {

    private Integer id;

    private String lastName;

    private String email;

    private String gender;


    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public Integer getId() {
        return id;
    }

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

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", lastName='" + lastName + '\'' +
                ", email='" + email + '\'' +
                ", gender='" + gender + '\'' +
                '}';
    }
}

5.2 加载核心配置文件，获取SqlSessionFactory

String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

5.3 获取SqlSession对象，执行SQL语句

SqlSession session = sessionFactory.openSession();
List<User> employeeList = session.selectList("suibian.selectEmployee");

5.4 释放资源

session.close();