超详细的mybatis连接数据库（入门使用）

    4.0.0

    org.example
    2022227
    1.0-SNAPSHOT
    

        
            mysql
            mysql-connector-java
            5.1.9
        

        
            org.mybatis
            mybatis
            3.5.1
        

        
            com.github.pagehelper
            pagehelper
            5.1.10
        
        
            junit
            junit
            4.12
            test
        

    

    
        
        
            
                src/main/java
                
                    ***.xml
                
                false
            
        

    

package com.zhangshaopeng.pojo;

    public class User {
        private int id;
        private String name;
        private int qua;

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

        public int getId() {
            return id;
        }

        public String getName() {
            return name;
        }

        public int getQua() {
            return qua;
        }

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

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

        public void setQua(int qua) {
            this.qua = qua;
        }

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

package com.zhangshaopeng.dao;

import com.zhangshaopeng.pojo.User;

public interface UserDao {
    User selectById(Integer integer);
}

package com.zhangshaopeng.utils;

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

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

public class MybatisUtils {
    private static SqlSessionFactory factory=null;
    static {
        String config = "mybatis.xml";
        try {
            InputStream inputStream = Resources.getResourceAsStream(config);
            factory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSession getSqlSession(){
        SqlSession sqlSession = null;
        if(factory != null){
            sqlSession = factory.openSession();
        }
        return sqlSession;
    }
}

    
        select * from machain.machain where id = #{id}
    

package com.zhangshaopeng;

import com.zhangshaopeng.dao.UserDao;
import com.zhangshaopeng.pojo.User;
import com.zhangshaopeng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class MyTest {
    @Test
    public void t(){
        SqlSession session = MybatisUtils.getSqlSession();
        UserDao dao = session.getMapper(UserDao.class);
        User user = dao.selectById(1);
        System.out.println(user);
        session.close();
    }
}