Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://192.168.5.83:1433;DatabaseName=xishi","sa","sa");
PreparedStatement ps=con.prepareStatement(sql,ResultSet.TYPE_SCROLL_SENSITIVE ,ResultSet.CONCUR_UPDATABLE );
ResultSet rs=ps.executeQuery();
rs.close();
//java中结果集调用close()方法对象会立刻垃圾掉吗?
rs = ps.executeQuery();
//还是当rs指向新对象的时候才会垃圾。