Mybatis

Mybatis整體架構

環境;

jdk1.8

myeclipse2015

mysql5.0

1.新建Java project

2.導入mybatis的jar包、lib第三方jar包以及jdbc驅動jar包（使用maven的話無需這麼麻煩，只寫配置文件導入就好）

複製jar包--粘貼進項目--選中jar包--右鍵build path--add to build path

 

3.src右鍵 -- new -- file 取名mybatis.xml

<?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/myblog?useUnicode=true&amp;characterEncoding=UTF8" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
	 
	<mappers>
		<mapper resource="mapper/StudentMapper.xml" />
	</mappers>
</configuration>

4.demo01.java文件測試

package demo;

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;

import entity.Student;

public class Demo01 {

	public static void main(String[] args) {
		try {
			//從配置文件中構建SqlSessionFactory工廠對象
			InputStream inputStream = Resources.getResourceAsStream("mybatis.xml");
			SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		
			//獲取sqlsession對象
			SqlSession session=sqlSessionFactory.openSession();
			
			try {
				//通過SqlSession對象進行數據庫各種操作：selectOne(),selectList(),update()...
				Student stu=session.selectOne("mapper.StudentMapper.selectStudentById",0);
				if(stu==null){
					System.out.println("沒有找到！");
				}else{
					System.out.println(stu);
				}
			} finally {
				session.close();
			}
		
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

}

5.StudentMapper.xml

<?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">
<!-- namespace必須唯一 -->
<mapper namespace="mapper.StudentMapper">
<resultMap type="entity.Student" id="baseResultMap">
	<id column="SID" property="sid" jdbcType="INTEGER"/>
	<result column="SNAME" property="sname" jdbcType="VARCHAR"/>
	<result column="SAGE" property="sage" jdbcType="INTEGER"/>
</resultMap>


	<!-- 根據id查詢 -->
    <select id="selectStudentById" parameterType="int" resultMap="baseResultMap">
    <!-- 如果實體類屬性名與表中字段一致則寫* -->
        select * from student where sid = #{sid}
    </select>
</mapper>

6.POJO類只有三個屬性 sid 、sname、sage