Mybatis 入门教程

实验环境

IDE:eclipse neon.3
数据库：mysql Ver 14.14 Distrib 5.6.36, for Win64 (x86_64)

工程目录

源代码

• database

create database mybatis;
use mybatis;
CREATE TABLE users(id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20), age INT);
INSERT INTO users(NAME, age) VALUES('Tom', 12);
INSERT INTO users(NAME, age) VALUES('Jack', 11);

• conf.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.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="dmw123456" />
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/dmw/bean/UserMapper.xml" />
    </mappers>

</configuration>

• 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.dmw.bean.UserMapper">
    <select id="getUser" parameterType="int"
        resultType="com.dmw.bean.User">
        select * from users where id=#{id}
    </select>
</mapper>

• User.java

package com.dmw.bean;
/**
 *@Author dmw
 *@Date 2018年2月1日 下午2:37:07
 *
*/

public class User {
    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public String getName() {
        return name;
    }
    public int getAge() {
        return age;
    }
    public void setId(int id) {
        this.id = id;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }

}

• Test.java

package com.dmw.bean;

import java.io.IOException;
import java.io.Reader;

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

public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String resource = "conf.xml";

        // 加载 mybatis 的配置文件（它也加载关联的映射文件）
        Reader reader = null;
        try {
            reader = Resources.getResourceAsReader(resource);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 构建 sqlSession 的工厂
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
        // 创建能执行映射文件中 sql 的 sqlSession
        SqlSession session = sessionFactory.openSession();
        // 映射 sql 的标识字符串

        String statement = "com.dmw.bean.UserMapper" + ".getUser";
        // 执行查询返回一个唯一 user 对象的 sql
        User user = session.selectOne(statement, 2);
        System.out.println("id:"+user.getId());
        System.out.println("name:"+user.getName());
        System.out.println("age:"+user.getAge());
    }

}