study Mybatis step by step

1. 简单查询
   一、首先创建下载mybatis的相关jar包和数据库的相关jar包，mybatis的jar包的官方下载地址http://mybatis.github.io/
   二、建立一个java项目并且将刚才下在的jar包放在相应的文件下面，然后参照到项目中
   三、建立mybatis-config.xml 配置文件如下：

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.2//EN" 
   "http://mybatis.org/dtd/mybatis-3-config.dtd">
   <configuration>
   
   	<!-- properties for the mybatis configuration -->
   	<properties>
   		<property name="driver" value="com.mysql.jdbc.Driver"/>
   		<property name="url" value="jdbc:mysql://localhost:3306/test"/>
   		<property name="username" value="root"/>
   		<property name="password" value=""/>
   	</properties>
   	
   	<!-- java type mapping -->
   	<typeAliases>
   		<typeAlias alias="Course"  type="com.mybatis.in.Course"/>
   	</typeAliases>
   	
   	<!-- environment configuration -->
   	<environments default="development">
   		<environment id="development">
   			<transactionManager type="JDBC">
   			</transactionManager>
   			<!-- database connection configuration -->
   			<dataSource type="POOLED">
   				<property name="driver" value="${driver}"/>
   				<property name="url" value="${url}"/>
   				<property name="username" value="${username}"/>
   				<property name="password" value="${password}"/>
   			</dataSource>
   		</environment>
   	</environments>
   
   	<!-- mapper configuration file -->
   	<mappers>
   		<mapper resource="com/test/mybatis/CourseMapper.xml"/>
   	</mappers>
   	
   </configuration>

   
   四、在com.test.mybatis下面建立一个CourseMapper.xml作为course的映射配置文件
   

   <?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">
   
   <!-- configuration for course mapper -->
   <mapper namespace="com.mybatis.in.CourseMapper"> 
   	<!-- mapping the course table and java course type-->
   	<resultMap id="courseMap" type="Course">
   		<id property="courseId" column="courseId"/>
   		<result property="courseType" column="courseType"/>
   		<result property="courseName" column="courseName"/>
   	</resultMap>
   	
   	<!-- configuration for the SQL -->
   	<select id="getCourses" resultMap="courseMap">
   		<![CDATA[select courseId,courseType,courseName from course]]>
   	</select>
   </mapper>

   五、建立CourseMapper接口和Course类
   
   CourseMapper
   
   

   package com.mybatis.in;
   
   import java.util.List;
   
   public interface CourseMapper {
   
   	public List<Course> getCourses();
   }
   
   

   
   Course
   

   package com.mybatis.in;
   
   public class Course {
   
   	private String courseId;
   	private String courseName;
   	private String courseType;
   	public String getCourseId() {
   		return courseId;
   	}
   	public void setCourseId(String courseId) {
   		this.courseId = courseId;
   	}
   	public String getCourseName() {
   		return courseName;
   	}
   	public void setCourseName(String courseName) {
   		this.courseName = courseName;
   	}
   	public String getCourseType() {
   		return courseType;
   	}
   	public void setCourseType(String courseType) {
   		this.courseType = courseType;
   	}
   	
   	
   }
   

   
   
   完成以上五个步骤，一个简单的Mybatis查询就建立好了，下面我们可以写一段程序测试一下我们上面的配置是否正确
   

   package com.tests;
   
   import java.io.IOException;
   import java.util.List;
   
   import org.apache.ibatis.io.Resources;
   import org.apache.ibatis.session.SqlSession;
   import org.apache.ibatis.session.SqlSessionFactory;
   import org.apache.ibatis.session.SqlSessionFactoryBuilder;
   
   import com.mybatis.in.Course;
   import com.mybatis.in.CourseMapper;
   
   public class Main {
   
   	/**
   	 * @param args
   	 * @throws IOException 
   	 */
   	public static void main(String[] args) throws IOException {
   
   		SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
   		SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(Resources.getResourceAsStream("mybatis-config.xml"));
   		SqlSession session = sqlSessionFactory.openSession();
   		
   		CourseMapper courseMapper =session.getMapper(CourseMapper.class);
   		List<Course> courses = courseMapper.getCourses();
   		System.out.println(courses.size());
   		session.close();
   		
   	}
   
   }