MybatisUtil的使用，便于产生SqlSession

简化代码，实现一个静态的工具类来实现获取SqlSession

主要有getSqlSessionFactory（）和getSqlSession()

public class MybatisUtil {
        
        private static SqlSessionFactory sqlSessionFactory;
        
        /**
         * 构建SqlSessionFactory工厂
         */
        public static SqlSessionFactory getSqlSessionFactory(){
            if(sqlSessionFactory==null){
                
                try {
                    //通过配置文件获取输入流
                    InputStream inputStream=Resources.getResourceAsStream("mybatis-config.xml"); 
                    //通过Builder和输入流构建sqlSessionFactory工厂
                     sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
                } catch (IOException e) {                    
                    e.printStackTrace();
                }
                
            }
            return sqlSessionFactory;
        }
        
        /**
         * 获取sqlSession
         */
        public static SqlSession getSqlSession(){
          return getSqlSessionFactory().openSession();   
        }
}