使用MyBatis的步骤

1.创建空的Java工程，安装MyBatis依赖

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0"

         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>

    <artifactId>mybatis03</artifactId>

    <version>1.0-SNAPSHOT</version>

    <packaging>jar</packaging>

    <build>

        <plugins>

            <plugin>

                <groupId>org.apache.maven.plugins</groupId>

                <artifactId>maven-compiler-plugin</artifactId>

                <version>3.8.0</version>

                <configuration>

                    <source>1.8</source>

                    <target>1.8</target>

                </configuration>

            </plugin>

        </plugins>

    </build>

    <dependencies>

        <dependency>

            <groupId>org.mybatis</groupId>

            <artifactId>mybatis</artifactId>

            <version>3.5.6</version>

        </dependency>

        <dependency>

            <groupId>mysql</groupId>

            <artifactId>mysql-connector-java</artifactId>

            <version>8.0.23</version>

        </dependency>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.12</version>

            <scope>test</scope>

        </dependency>

    </dependencies>

</project>

2.创建JavaBean类

在src/main/java下新建com.ttpfx.domain包，并创建User类：

package com.ttpfx.domain;

import java.util.Date;

public class User {

    private Integer id;

    private String username;

    private Date birthday;

    private String sex;

    private String address;

    public Integer getId() {

        return id;

    }

    public void setId(Integer id) {

        this.id = id;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public Date getBirthday() {

        return birthday;

    }

    public void setBirthday(Date birthday) {

        this.birthday = birthday;

    }

    public String getSex() {

        return sex;

    }

    public void setSex(String sex) {

        this.sex = sex;

    }

    public String getAddress() {

        return address;

    }

    public void setAddress(String address) {

        this.address = address;

    }

    @Override

    public String toString() {

        return "User{" +

                "id=" + id +

                ", username='" + username + '\'' +

                ", birthday=" + birthday +

                ", sex='" + sex + '\'' +

                ", address='" + address + '\'' +

                '}';

    }

}

3.创建Dao接口

在src/main/java新建com.ttpfx.dao包，并创建UserDao接口:

package com.ttpfx.dao;

import com.ttpfx.domain.User;

import java.util.List;

public interface UserDao {

    List<User> getAll();

}

4.创建XML映射文件

在src/main/resources下创建com/ttpfx/dao/UserDao.xml

注意事项：

xml文件的路径和名称与com.ttpfx.dao.UserDao接口对应
mapper标签的namespace属性为UserDao的全限定类名
select标签的id与UserDao接口的方法对应
指定select标签的resultType为User类的全限定类名

<?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.ttpfx.dao.UserDao">

    <select id="getAll" resultType="com.ttpfx.domain.User">

        select id, username, birthday, sex, address from user;

    </select>

</mapper>

5.创建MyBatis主配置文件

在src/main/resources下创建SqlMapConfig.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>

    <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/t_mybatis"/>

                <property name="username" value="root"/>

                <property name="password" value="123456"/>

            </dataSource>

        </environment>

    </environments>

    <mappers>

        <mapper resource="com/ttpfx/dao/UserDao.xml"/>

    </mappers>

</configuration>

6.测试使用

在src/test/java新建com.ttpfx.test包，并创建MybatisTest类：

package com.ttpfx.test;

import com.ttpfx.dao.UserDao;

import com.ttpfx.domain.User;

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.InputStream;

import java.util.List;

public class MybatisTest {

    public static void main(String[] args) throws Exception {

        // 1.读取配置文件

        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");

        // 2.创建SqlSession工厂

        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();

        SqlSessionFactory sqlSessionFactory = builder.build(in);

        // 3.创建SqlSession

        SqlSession sqlSession = sqlSessionFactory.openSession();

        // 4.创建UserDao动态代理

        UserDao userDao = sqlSession.getMapper(UserDao.class);

        // 5.使用userDao

        List<User> list = userDao.getAll();

        list.forEach(System.out::println);

        // 6.销毁资源

        sqlSession.close();

        in.close();

    }

}

巴特西