Java:MyBatis简单入门

简介:

iBatis更名为MyBatis，作出了些修改.如以前使用SqlMapClient进行数据库操作，现在使用SqlSession.

jar包

普通的javaBean: domain.User

与bean对应的SQL映射文件: maps/User.xml

MyBatis需要的配置文件: mybatis.cfg.xml

1.需要的jar包:mybatis-3.0.2.jar(只有此一个是必须的，比iBatis清楚多了).

2.类User:

packagedomain;

publicclassUser{

privateintid;

privateStringname;

publicUser(){}

publicUser(Stringname) {this(0,name); }

publicUser(intid,String name) {

this.id=id;

this.name=name;

}

publicintgetId(){returnid;}

publicvoidsetId(intid){this.id=id; }

publicStringgetName() {returnname;}

publicvoidsetName(Stringname) {this.name=name; }

@Override

publicStringtoString() {return"ID:"+id+",Name: "+name;}

3.User.xml映射文件:

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

<!DOCTYPE mapperPUBLIC

"-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="User">

<select id="selectUser" parameterType="int"resultType="User"><![CDATA[

select *from user where id = #{id}

]]></select>

</mapper>

4.MyBatis需要的配置文件:

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

<!DOCTYPEconfiguration PUBLIC

"-//mybatis.org//DTD Config 3.0//EN"

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

<configuration>

<typeAliases>

<typeAlias alias="User" type="domain.User" />

</typeAliases>

<environments default="development">

<environment id="development">

<transactionManagertype="JDBC"/>

<dataSource type="POOLED">

<property name="driver" value="com.mysql.jdbc.Driver" />

<property name="url" value="jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=UTF-8"/>

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

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

</dataSource>

</environment>

</environments>

<mappers>

<mapper resource="maps/User.xml" />

</mappers>

</configuration>

5.使用MyBatis访问数据库:

import java.io.IOException;

import java.io.Reader;

import org.apache.ibatis.io.Resources;

importorg.apache.ibatis.session.SqlSession;

importorg.apache.ibatis.session.SqlSessionFactory;

importorg.apache.ibatis.session.SqlSessionFactoryBuilder;

import domain.User;

publicclass Test {

publicstatic void main(String[] args) throws IOException {

Stringresource = "mybatis.cfg.xml";

Readerreader = Resources.getResourceAsReader(resource);

SqlSessionFactory ssf = newSqlSessionFactoryBuilder().build(reader);

SqlSessionsession = ssf.openSession();

try {

User user = (User)session.selectOne("selectUser","3");

System.out.println(user);

}catch (Exception e) {

e.printStackTrace();

}finally {

session.close();

}

}