创建工具类的思路的分析: 1. 不让别人来创建对象,就用private私有构造方法化,工具类都是静态的类名点调用,声明所欲变量,提供静态代码块.给变量赋值,创建方法举例:public class MapperFactory{ private MapperFactory(){}; private static SqlSessionFactory factory; private static ThreadLocal<SqlSession> tl = new ThreadLocal<SqlSession>();static{InputStream in = null; try { //1.读取mybatis主配置文件 in = Resources.getResourceAsStream("SqlMapConfig.xml"); //2.创建构建者对象 SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //3.使用构建者创建SqlSessionFactory工厂 factory = builder.build(in); }catch (Exception e){ //打印异常信息到控制台 e.printStackTrace(); //抛出错误提示程序终止执行 throw new ExceptionInInitializerError("初始化SqlSessionFactory失败"); }finally { //释放流对象 if(in != null){ try{ in.close(); }catch (Exception e){ e.printStackTrace();try each的位置,