ex3_2bu2.jsp

黑魔方JSP基础教程源代码(耿祥义编著)是这里有课件和jsp源代码

 <%String textContent=request.getParameter("girl");
     double number=0,r=0;
     
     try{ number=Double.parseDouble(textContent);
          if(number>=0)
             {r=Math.sqrt(number) ;
              out.print("<BR>"+number+"的平方根：");
              out.print("<BR>"+r);
             }
          else
             {out.print("<BR>"+"请输入一个正数");
             }
        }
     catch(NumberFormatException e)
        {out.print("<BR>"+"请输入数字字符");
        }
    %>