MyBatis的入门案例

1.MyBatis的结构

2.MyBatis入门案例

a.创建java项目，并在其中导入相关开发包

b.导入约束文件

http://mybatis.org/dtd/mybatis-3-config.dtd

c.编写配置文件sqlMapConfig.xml，配置文件

<?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>
    
    <!-- 配置数据源 -->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    
</configuration>

d.创建表，创建bean

（1）创建表

-- 创建数据库
create database mybatis;
-- 创建表
use mybatis;
create table user (
    id int primary key auto_increment,
    name varchar(255),
    age int(10)
);
-- 插入数据
insert into user values (null,'aaa',19),(null,'bbb',29),(null,'ccc',39),(null,'ddd',22),(null,'eee',33);

（2）创建bean

package cn.tedu.mybatis.beans;

public class User {
    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
}

（3）编写映射文件，描述bean和表sql的映射关系

<?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">

<mapper namespace="cn.tedu.mybatis.beans.UserMapper">
    <select id="queryAll" resultType="cn.tedu.mybatis.beans.User">
        select * from user
    </select>
</mapper>

（4）将映射文件配置到sqlMapConfig.xml中

    <!-- 声明映射文件 -->
    <mappers>
        <mapper resource="cn/tedu/mybatis/beans/UserMapper.xml"/>
    </mappers>

（5）测试类测试

package cn.tedu.mybatis.test;

import java.io.InputStream;
import java.util.Arrays;
import java.util.List;

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 org.junit.Test;

import cn.tedu.mybatis.beans.User;

public class MybatisTest {
    
    @Test
    public void test01() throws Exception{
        // 1.读取MyBatis核心配置文件
        InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
        // 2.根据配置文件创建sqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        // 3.创建sqlSession
        SqlSession session = factory.openSession();
        // 4.执行操作
        List<User> list = session.selectList("cn.tedu.mybatis.beans.UserMapper.queryAll");
        // 5.遍历结果
        System.out.println(Arrays.toString(list.toArray()));
    }
}

（6）调用过程