mybaits 创建dao的两种实现方式

本文主要是介绍mybaits 创建dao的两种实现方式，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

一.传统的实现dao

1.1 工程结构

1.2 创建dao层

1.dao层接口

package com.mybaits.demo.dao;import com.mybaits.demo.bean.User;import java.io.IOException;
import java.util.List;public interface UserMapper {List<User> findAll() throws IOException;
}

2.dao的实现层

package com.mybaits.demo.dao.impl;import com.mybaits.demo.bean.User;
import com.mybaits.demo.dao.UserMapper;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;/*** @ClassName: UserDaoImpl* @Description: TODO* @Author: liujianfu* @Date: 2021/01/30 21:57:31 * @Version: V1.0**/
public class UserMapperImpl implements UserMapper {@Overridepublic List<User> findAll() throws IOException {//加载核心配置文件InputStream resourcesAsStream= Resources.getResourceAsStream("mybaitsConfig.xml");//获得sqlsession 工厂对象SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourcesAsStream);//获得sqlsession对象SqlSession sqlSession=sqlSessionFactory.openSession();//执行sqlList<User> userList=sqlSession.selectList("yonghuMapper.findAll");//打印资源System.out.println("userlist:"+userList);//关闭释放资源sqlSession.close();return userList;}
}

1.2 创建service层

1.service的接口

package com.mybaits.demo.service;import com.mybaits.demo.bean.User;import java.io.IOException;
import java.util.List;public interface UserService {List<User> findAll() throws IOException;
}

2.service的实现层

package com.mybaits.demo.service.impl;import com.mybaits.demo.bean.User;
import com.mybaits.demo.dao.UserMapper;
import com.mybaits.demo.dao.impl.UserMapperImpl;
import com.mybaits.demo.service.UserService;import java.io.IOException;
import java.util.List;/*** @ClassName: UserServiceImpl* @Description: TODO* @Author: liujianfu* @Date: 2021/01/30 22:00:02 * @Version: V1.0**/
public class UserServiceImpl implements UserService {@Overridepublic List<User> findAll() throws IOException {UserMapper  userMapper=new UserMapperImpl() ;List<User> userList= userMapper.findAll();System.out.println("");return userList;}
}

3.mapper：

1.3 调用

二.代理方式实现dao

2.1 实现方式概览

2.2 mapper.xml的配置

2.3 dao接口的配置

package com.mybaits.demo.dao;import com.mybaits.demo.bean.User;import java.io.IOException;
import java.util.List;public interface UserMapper {List<User> findAll() throws IOException;
}

2.4 service层接口

1.service接口

package com.mybaits.demo.service;import com.mybaits.demo.bean.User;import java.io.IOException;
import java.util.List;public interface UserService2 {List<User> findAll() throws IOException;
}

2.services实现层

package com.mybaits.demo.service.impl;import com.mybaits.demo.bean.User;
import com.mybaits.demo.dao.UserMapper;
import com.mybaits.demo.service.UserService2;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;/*** @ClassName: UserServiceImpl2* @Description: TODO* @Author: liujianfu* @Date: 2021/01/30 23:56:52 * @Version: V1.0**/
public class UserServiceImpl2 implements UserService2 {@Overridepublic List<User> findAll() throws IOException {//加载核心配置文件InputStream resourcesAsStream= Resources.getResourceAsStream("mybaitsConfig.xml");//获得sqlsession 工厂对象SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourcesAsStream);//获得sqlsession对象SqlSession sqlSession=sqlSessionFactory.openSession();//产生代理对象UserMapper userMapper=sqlSession.getMapper(UserMapper.class);List<User> userList= userMapper.findAll();//打印资源System.out.println("userlist:"+userList);//关闭释放资源sqlSession.close();return userList;}
}