Idea2021.3.1 搭建第一个Mybatis程序

1.导入相关依赖：pom.xml导入 Mybatis依赖

 
        
            junit
            junit
            4.11
            test
        

        
        
            org.mybatis
            mybatis
            3.5.9
        


    

2.配置XML 配置文件中包含了对 MyBatis 系统的核心设置

在resources中创建mybatis.xml文件

 新建完成之后将以下代码直接复制进去

注意：修改url，username，password

3.编写util
 

package com.tao.util;

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;

//sqlSessionFactory -->sqlSession
public class mybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream =  inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //有了sqlSessionFactory，就可以获得sqlsession的实例了
    //sqlSession 完全包含了面向数据库执行sql命令所需的所有方法
    public static SqlSession getSqlsession(){
        return sqlSessionFactory.openSession();
    }

}

4.写实体类
 

package com.tao.info;

public class userinfo {

    private int id;
    private String name;

    public userinfo() {
    }

    public userinfo(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "userInfo{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

 5.写接口
 

package com.tao.dao;

import com.tao.info.userinfo;

import java.util.List;

public interface UserDao {

    List getUserList();

}

6.在resources下配置mapper.XML
 

`

    
        select * from user
    

namesepace:为接口路径
id：接口中的方法名
resultType:为实体类路径(sql语句返回值)

7.测试
 

package org.tao.dao;

import com.tao.dao.UserDao;
import com.tao.info.userinfo;
import com.tao.util.mybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserDaoTest {

    @Test
    public void test(){

        //获取SqlSession对象
        SqlSession sqlsession = mybatisUtils.getSqlsession();

        //getMapper
        UserDao mapper = sqlsession.getMapper(UserDao.class);
        List userList = mapper.getUserList();

        for (userinfo userinfo : userList) {
            System.out.println(userinfo);
        }


        //关闭sqlSession
        sqlsession.close();
    }


}

运行之后报错 

资源导出问题，找不到 
pom.xml中导入如下代码：
 

  
            
                
                    src/main/java
                    
                        **/*.xml
                        **/*.properties
                    
                

                
                    src/main/resources
                    
                        **/*.xml
                        **/*.properties
                    
                
            
        

8.运行