MyBatis | Maven工程 MyBatis环境搭建

Maven工程导入坐标（jar包）mybatis，mysql-connector-java，（log4j，junit等）

编写mybatis-config.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>
	<!-- 引入外部配置文件 -->
	<properties resource="database.properties" />
	<!-- 一些配置 -->
	<settings>
		<setting name="logImpl" value="LOG4J"/>
	</settings>
	<!-- 返回对象位置 -->
	<typeAliases>
		<package name="com.chaofan.pojo"/>
	</typeAliases>
	<!-- 数据库信息 -->
	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC"></transactionManager>
			<dataSource type="POOLED">
				<property name="driver" value="${driver}"/>
				<property name="url" value="${url}"/>
				<property name="username" value="${user}"/>
				<property name="password" value="${password}"/>
			</dataSource>
		</environment>
	</environments>
	<!-- 扫描mapper.xml文件 -->
	<mappers>
		<mapper resource="com/chaofan/mapper/UserMapper.xml"/>
	</mappers>
</configuration>

编写mapper写法

<?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.chaofan.dao.IUserMapper">
	
	<!-- 查询所有用户 -->
	<select id="listUser" resultType="User">
		select userName, phone from smbms_user
	</select>
	
	<!-- 查询总用户数 -->
	<select id="totalCount" resultType="int">
		select count(id) from smbms_user
	</select>
</mapper>

注意：namespace中的地址是接口位置，id中的值是接口对应的方法名字

MyBatisUtils工具类

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;


public class MyBatisUtils {

	private static SqlSessionFactory sqlSessionFactory;
	
	static {
		String path = "mybatis-config.xml";
		try {
			InputStream is = Resources.getResourceAsStream(path);
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}
	
	// 获取SqlSession
	public static SqlSession getSqlSession() {
		return sqlSessionFactory.openSession();
		// 设置事务自动提交
		// return sqlSessionFactory.openSession(true);
	}
	
	// 关闭
	public static void closeSqlSession(SqlSession sqlSession) {
		if (sqlSession != null) {
			sqlSession.close();
		}
	}
}