封装Mybatis的工具类获取sqlSession对象

package com.bjpowernode.utils;

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;

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

============使用工具类

package com.bjpowernode;

import com.bjpowernode.domain.Student;
import com.bjpowernode.utils.MybatisUtil;
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 MyApp2 {
    public static void main(String[] args) throws IOException {

        SqlSession sqlSession = MybatisUtil.getSqlSession();
        String sqlId ="com.bjpowernode.dao.StudentDao"+"."+"selectStudents";
        List<Student> studentList = sqlSession.selectList(sqlId);
        for (Student stu:studentList
             ) {
            System.out.println(stu);
        }
        sqlSession.close();

    }
}