通过表单向servlet提交数据不成功。
在givenumber.jsp页面中输入一个正实数,求其平方根。
但是输入正实数后,点提交时。得不出结果。
givenumber.jsp的代码如下:
<%@page contentType="text/html;charset=GB2312"%>
<Html>
	<form action="/servlet/Sqrt" method="get">
	<input type="text" name="number"/>
	<input type="Submit" name="提交"/>
	</form>
</Html>
Servlet的代码如下:
public class Sqrt extends HttpServlet{
	protected void service(HttpServletRequest req, HttpServletResponse resp)
	throws 
ServletException, 
IOException {
		PrintWriter out = resp.getWriter();
		resp.setContentType("text/html;charset=GB2312");
		out.println("<html><body>");
		String number = req.getParameter("number");
		double n=0;
		try{
			n=Double.parseDouble("number");
			out.print("<BR>"+Math.sqrt(n));	
		   }catch (
NumberFormatException e) {	
		   	}
		   out.println("</body></html>");
	}
}
web.xml的代码如下:
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"  
	xmlns="http://java.sun.com/xml/ns/j2ee"  
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<servlet>
		<servlet-name>pingfang</servlet-name>
		<servlet-class>com.wzh.servlet.Sqrt</servlet-class>
	</servlet>
	<mapping-servlet>
		<servlet-name>pingfang</servlet-name>
		<url-pattern>/servlet/Sqrt</url-pattern>
	</mapping-servlet>
   <welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
</web-app>
------解决方案--------------------
1    把这句 <form action="/servlet/Sqrt" method="get"> 改成:
<form action="servlet/Sqrt" method="get">   //去掉前面的斜杠.
2    把这句   n=Double.parseDouble("number"); 该成:
n=Double.parseDouble(number);
试试.