MyBitis(iBitis)系列随笔之一：MyBitis入门实例

MyBits前身是iBitis,相对于Hibernate而言,它是半自动化ORM框架。本着分享和学习的目的，笔者将陆续把学习笔记与代码贴出，希望对想学习mybitis的同窗们有所帮助。
鉴于我的测试数据库是mysql，同仁们现在把mysql装好，然后准备好mysql驱动以及从官网上下载mybitis(http://code.google.com/p/mybatis/)。我下载的是最新的mybatis-3.2.2.zip。

创建数据库test

然后创建表t_user

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DROP TABLE IF EXISTS `t_user`;

CREATE TABLE `t_user` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`name` varchar(20) DEFAULT NULL,

`pass` varchar(20) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=gbk;

INSERT INTO `t_user` VALUES ('1', 'ssssssssssssssss', 'ddsssssssdd');

然后创建与表对应的Java bean对象

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<span style="color:#000000;">package com.jefry;

public class User {

private int id;

private String name;

private String pass;

public String getPass() {

return pass;

}

public void setPass(String pass) {

this.pass = pass;

}

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;

}

}</span>

接下来，在classpath目录下面创建与配置mybatis-config.xml文件

内容如下：

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<?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/test"/>

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

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

</dataSource>

</environment>

</environments>

<mappers>

<!--这个文件下面将创建-->

<mapper resource="com/jefry/UserMapper.xml"/>

</mappers>

</configuration>

通过mybatis-config.xml中<mapper resource="com/jefry/UserMapper.xml"/>配置项，我们在包com.jefry下面创建文件UserMapper.xml
内容如下：

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<?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="User">

<!--resultType 表示com.jefry.User这样一个实体对象 -->

<select id="selectUser" parameterType="int" resultType="com.jefry.User">

select * from t_user where id = #{id}

</select>

</mapper>

编写测试代码

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package com.jefry;

import java.io.IOException;

import java.io.InputStream;

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 {

static String resource = "mybatis-config.xml";

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

// TODO Auto-generated method stub

InputStream inputStream = Resources.getResourceAsStream(resource);

SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

SqlSession session = sqlSessionFactory.openSession();

try {

//User.selectUser中User对应UserMapper.xml文件中标签<mapper namespace="User"> namespace的值

//selectUser 对应UserMapper.xml文件中标签<select id="selectUser" parameterType="int" resultType="com.jefry.User">中id值

User user = session.selectOne("User.selectUser", 1);

System.out.println("user.getName()=" + user.getName());

} finally {

session.close();

}

}

}

通过运行就可以结果：user.getName()=ssssssssssssssss