07_MyBatis原始的Dao编写方法

package com.Higgin.Mybatis.dao;

import com.Higgin.Mybatis.po.User;

public interface UserDao {
    //根据id查询用户信息
    public User findUserById(int id) throws Exception;
    
    //添加用户信息
    public void insertUser(User user) throws Exception;
    
    //删除用户信息
    public void deleteUser(int id) throws Exception;
}

package com.Higgin.Mybatis.dao;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import com.Higgin.Mybatis.po.User;

public class UserDaoImpl implements UserDao{
    //需要向Dao实现类中注入SqlSessionFactory
    private SqlSessionFactory sqlSessionFactory;
    //这里通过构造方法注入
    public UserDaoImpl(SqlSessionFactory sqlSessionFactory){
        this.sqlSessionFactory=sqlSessionFactory;
    }
    
    @Override
    public User findUserById(int id) throws Exception {
        SqlSession sqlSession=sqlSessionFactory.openSession();
        User user=sqlSession.selectOne("test.findUserById",id);
        //补充一个释放资源的代码
        sqlSession.close();
        return user;
    }

    @Override
    public void insertUser(User user) throws Exception {
        SqlSession sqlSession=sqlSessionFactory.openSession();
        sqlSession.insert("test.insertUser",user);
        //提交事务,必须！
        sqlSession.commit();
        //补充一个释放资源的代码
        sqlSession.close();
    }

    @Override
    public void deleteUser(int id) throws Exception {
        SqlSession sqlSession=sqlSessionFactory.openSession();
        sqlSession.delete("test.deleteUser",id);
        //提交事务
        sqlSession.commit();
        //补充一个释放资源的代码
        sqlSession.close();
    }
}

package com.Higgin.Mybatis.dao.test;

import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;
import com.Higgin.Mybatis.dao.UserDao;
import com.Higgin.Mybatis.dao.UserDaoImpl;
import com.Higgin.Mybatis.po.User;

public class UserDaoTest{
    
    private SqlSessionFactory sqlSessionFactory; 
    
    //此方法在执行testFindUserById() 之前执行
    @Before
    public void setUp() throws Exception {
        //创建sqlSessionfactory
        //MyBatis配置文件
        String resource="SqlMapConfig.xml";
        //得到配置文件流
        InputStream inputStream=Resources.getResourceAsStream(resource);
        //创建会话工厂，传入MyBatis的配置文件信息  
　　　　　//这里千万别写成SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
　　　　//不然会NullPointerException报错
        sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void testFindUserById() throws Exception {
        //创建UserDao的对象
        UserDao userDao =new UserDaoImpl(sqlSessionFactory);
        //调用UserDao的方法
        User user =userDao.findUserById(4);
        
        System.out.println(user.toString());
    }

}