我们需要到MyBatis官网下载架包.当然也可以使用Maven.

第一个工程

压缩包文件目录

压缩包文件目录
lib 文件夹: mybatis 依赖的架包
mybatis-3.4.2.jar: mybatis 核心架包.
mybatis-3.4.2.pdf: mybatis 使用手册(英文版).
我用的是 mysql 数据库别忘了对应的驱动.我用的是5.1版本的因为他支持 Java8.

创建工程并将mybatis加入工程中.

添加log4j.properties

MyBatis的 SQL 语句输出需要我们配置 log4j 并且级别为 DEBUG 才可以输出.下面是我的配置

#MyBatis configuration
log4j.rootLogger=DEBUG, stdout
log4j.logger.org.mybatis=DEBUG
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
#简洁 模式
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
#啰嗦 模式
#log4j.appender.stdout.layout.ConversionPattern=%5p %d %C - %m%n

XML 配置文件(Configuration XML)

此文件包含了对 MyBatis 系统的核心设置，包含获取数据库连接实例的数据源(DataSource)和决定事务作用域和控制方式的事务管理器(TransactionManager)

<?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="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://${ip}:${port}/${DataBaseName}"/>
                <property name="username" value="${UserName}"/>
                <property name="password" value="${PassWord}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="cc/ibadboy/mybatis/map/userMapper.xml"></mapper>
    </mappers>
</configuration>

创建实体类

public class User {
    private int userId;
    private String userName;
    private String userPwd;

    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }
    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                '}';
    }
}

Mapper映射文件

此文件用来配置 SQL 语句,结果集等.

<?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="cc.ibadboy.mybatis.entity">
    <select id="findById" resultType="String" parameterType="int">
        select userName from user where userId = #{id}
    </select>
</mapper>

编码实现

public class Test {
    public static void main(String[] agr){
        try {
            InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            SqlSession session = sqlSessionFactory.openSession();
            String userName = session.selectOne("findById",1);
            System.out.println(userName);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请结合 MyBatis3-配置详解 一起阅读.