mybatis快速入门--根据配置文件执行SQL语句

MyBatis 是一个可以自定义SQL、存储过程和高级映射的持久层框架。

使用的开发工具是Eclipse+mybatis-3.3.0-SNAPSHOT.jar+mysql-connector-java-5.1.7-bin.jar+mysql

下载mybatis-3.3.0-SNAPSHOT.jar网址：https://github.com/mybatis/mybatis-3/releases

创建工程：

在MySQL创建Test数据库：create database Test;

在Test中创建student表： CREATE TABLE `student` (

   `id` int(11) NOT NULL AUTO_INCREMENT,

   `username` varchar(20) DEFAULT NULL,

   `age` int(20) DEFAULT NULL,

   PRIMARY KEY (`id`)

 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

 

插入数据：insert into student(username,age)values('admin',20);

 

mybatis的重要配置文件，

 <?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>  

    <typeAliases>  

        <!--给实体类起一个别名 user -->  

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

    </typeAliases>  

    <!--数据源配置  这块用 mysql数据库 -->  

    <environments default="development">  

        <environment id="development">  

            <transactionManager type="jdbc" />  

            <dataSource type="POOLED">  

               <!-- 加载jdbc驱动-->

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

               <!-- MySQL  URL-->

                <property name="url" value="jdbc:mysql://localhost:3306/test" />  

               <!-- MySQL用户名-->

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

               <!-- MySQL密码-->

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

            </dataSource>  

        </environment>  

    </environments>  

    <mappers>  

        <!--user.xml装载进来  同等于把“dao”的实现装载进来 -->  

        <mapper resource="com/lcb/mybatis/user.xml" />  

    </mappers>  

</configuration>

创建User实体

 

public class User {

private int id;

private String username;  

    private int age;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

} 

    

    

}

 

mybatis需要的sql语句配置文件

 

<?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.lcb.domain.User">  

    <!-- selectOneId必须和接口中的方法名一样  返回一个resultType=User(要么是configuration.xml配置中起的别名或者是包名+实体类名)-->  

    <select id="selectOneId" parameterType="HashMap" resultType="User">  

        select  

        * from student where id=#{id}  

    </select>  

</mapper>

 

 

mybatis测试

public class MybatisTest {

private static SqlSessionFactory sqlSessionFactory = null;

private static SqlSession sqlSession = null;

static{

try {

//根据配置文件获取SqlSessionFactory

sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("configuration.xml"));

//根据SqlSessionFactory获取SqlSession

sqlSession = sqlSessionFactory.openSession(); 

} catch (IOException e) {

 

e.printStackTrace();

} 

}

private static SqlSessionFactory getSqlSessionFactory(){

return sqlSessionFactory;

}

 

private static SqlSession getSqlSession(){

return sqlSession;

}

/**

* @param args

*/

public static void main(String[] args) {

        // TODO Auto-generated method stub

        //SqlSession sqlSession = getSessionFactory().openSession();  

        //UserMapp userMapper = sqlSession.getMapper(UserMapper.class); 

        //selectOne("namespace+id", "需要的参数值")

        User user = sqlSession.selectOne("com.lcb.domain.User.selectOneId", 14);

        System.out.println(user.getUsername());  

}

 

}

 

//输出结果

admin