MyBatis编写Dao实现类

1、创建实现类

恢复我们的IUserDao.xml文件

UserDaoImpl.java

package com.tianyi.dao.impl;

import com.tianyi.dao.IUserDao;
import com.tianyi.javabean.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class UserDaoImpl implements IUserDao {
    private SqlSessionFactory factory ;
    public UserDaoImpl(SqlSessionFactory factory){
        this.factory=factory;
    }
    public List<User> findAll() {
        SqlSession session =factory.openSession();
        List <User> users=session.selectList("com.tianyi.dao.IUserDao.findAll");
        session.close();
        return users;
    }
}

2、修改测试类

MbTest.java

package com.tianyi.test;

import com.tianyi.dao.IUserDao;
import com.tianyi.dao.impl.UserDaoImpl;
import com.tianyi.javabean.User;
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;

public class MbTest {
    public static void main(String[] args) throws IOException {
        //1.读取配置文件
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建 SqlSessionFactory 的构建者对象
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        //3.使用构建者创建工厂对象 SqlSessionFactory
        SqlSessionFactory factory = builder.build(in);
//        //4.使用 SqlSessionFactory 生产 SqlSession 对象
//        SqlSession session = factory.openSession();
//        //5.使用 SqlSession 创建 dao 接口的代理对象
//        IUserDao userDao = session.getMapper(IUserDao.class);
        //产生实例对象
        IUserDao userDao=new UserDaoImpl(factory);
        //6.使用代理对象执行查询所有方法
        List <User>users = userDao.findAll();

        for(User user : users) {
            System.out.println(user);
        }
//        //7.释放资源
//        session.close();
        in.close();
    }
}