MyBatis第一个案例-----永远的HelloWorld 含所有代码

CREATE DATABASE mybatis;
USE mybatis;
CREATE TABLE emp(
id INT(11) PRIMARY KEY AUTO_INCREMENT,
last_name VARCHAR(255),
gender CHAR(1),
email VARCHAR(255)
);

package cn.bdqn.mybatis.been;

public class Emp {
	private Integer id;
	private String last_name;
	private String email;
	private String gender;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getLast_name() {
		return last_name;
	}
	public void setLast_name(String last_name) {
		this.last_name = last_name;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	@Override
	public String toString() {
		return "Emp [id=" + id + ", last_name=" + last_name + ", email="
				+ email + ", gender=" + gender + "]";
	}
	
	
}

<?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:名称空间  -->
<mapper namespace="cn.bdqn.mybatis.empMapper">
<!--
id,唯一标识 
resultType:返回值类型,bean的全限定名称

#{id},从传递过来的参数中取出id值,相当于换位符
 -->
<select id="selectEmp" resultType="cn.bdqn.mybatis.been.Emp">
select * from emp where id = #{id}
</select>
</mapper>

<?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/mybatis?"/>
<property name="username" value="root"/>
<property name="password" value="admin"/>
</dataSource>
</environment>
</environments>
<!--将我们写好的SQL映射文件一定要注册到全局配置文件中  -->
<mappers>
<mapper resource="empMapper.xml"/>
</mappers>
</configuration>

package cn.bdqn.mybatis.test;
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 cn.bdqn.mybatis.been.Emp;
public class MyBatisTest {
	/**
	 * 1.根据xml配置文件(全局配置文件),创建一个SqlSessionFactory对象
	 * 			有数据源的一些运行环境信息
	 * 2.	sql映射文件,配置了每一个sql,以及sql的封装规则等.
	 * 3将sql映射文件注册在全局配置文件中
	 * 4写代码:	
	 * 				1).根据全解决配置文件得到SqlSessionFactory;
	 * 				2)使用SqlSessionFactory工厂获取到SqlSession对象,使用SqlSession实例来执行增删改查
	 * 						一个SqlSession实例就是代表和数据库的一次会话
	 * 				3)使用sql的唯一标识来告诉MyBatis执行哪个sql,sql都是保存在SQL映射文件中(empMapper.xml)
	 * @throws IOException
	 */
	public void test() throws IOException{
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory =new SqlSessionFactoryBuilder().build(inputStream);
		/**
		 * 2.获取SqlSession的实例,能够直接执行已经映射的sql语句
		 * sql的唯一标识:statement Unique identifier matching the statement to use
		 * 执行sql要用的参数parameter A parameter object to pass to the statement.
		 */
		SqlSession openSession = sqlSessionFactory.openSession();
		/**
		 * openSession.selectOne(arg0, arg1)
		 * 第一个参数是:nameSpace+id
		 */
		try{
			Emp emp = (Emp)openSession.selectOne("cn.bdqn.mybatis.empMapper.selectEmp", 1);
			System.out.println(emp);
		}finally{
			openSession.close();
		}
		
	
	}

}