(一)、MyBatis初次体验

MyBatis是一个轻量级的ORM框架(个人理解成ORM)，操作方便，入门简单。写几篇文章记录一下自己的学习过程。

1、Configuration.xml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>
    <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://localhost:3306/mybatisdemo" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/mybatis/mapper/userMapping.xml"/>
     </mappers>
</configuration>

2、生成SqlSessionFactory

String resource = "configuration.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);

原则上一个数据源生成一个对应的SqlSessionFactory，但是每个线程要生成自己的SqlSession。

3、通过SqlSessionFactory生成SqlSession

 SqlSession session = factory.openSession(); 

4、进行增删改查操作

SqlSession session = factory.openSession();
try{
　　UserMapper userMapper = session.getMapper(UserMapper.class);
　　User user = new User();
　　user.setId(1);
　　user.setName("张山");
　　user.setDeptId(1);
　　userMapper.save(user);
　　session.commit();//一定要commit否则数据不会添加
}finally{
　　session.close();    
}

SqlSession session = factory.openSession();
try{
　　UserMapper userMapper = session.getMapper(UserMapper.class);
　　userMapper.deleteById(1);
　　session.commit();
}finally{
　　session.close();    
}

SqlSession session = factory.openSession();
try{
　　UserMapper userMapper = session.getMapper(UserMapper.class);
　　User user = new User();
　　user.setId(1);
　　user.setName("张大山");
　　user.setDeptId(1);
　　userMapper.update(user);
　　session.commit();//一定要commit否则数据不会添加
}finally{
　　session.close();    
}

SqlSession session = factory.openSession();
try{
　　UserMapper userMapper = session.getMapper(UserMapper.class);
　　User user = userMapper.queryById(1);
}finally{
　　session.close();    
}

增删改查的操作，比较简单。OK先写到这里！