wml与服务器交互 开发和服务器交互功能

现在很多人开发wml的应用了，但它们毕竟都是些静态的内容。如果我们要开发和服务器交互的功能呢？答案当然是我们可以使用Servlet技术。

看下面的例子：
<?xml version='1.0'?>
<DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">
 
<wml>
 
 <card id="Order" title="Query Inventory">
  <p>
  <select name="Items" title="Items">
   <option value="Books">Books</option>
   <option value="Music">Music</option>
   <option value="Video">Video</option>
   <option value="Software">Software</option>
  </select>
  </p>
  <do type="accept" label="Query">
   <go href="http://localhost:8080/ewap/wapservlet" method="get">
    <postfield name="Items" value="$(Items)"/>
   </go>
  </do>
 </card>
</wml>
用户可以从列表中选择Item,通过无线网络传输给服务器后Servlet通过request.getParameter()方法得到用户的选择并发送给用户，servlet的代码如下：

package com.j2medev.mingjava;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class WapServlet extends HttpServlet
{

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {
        String select = request.getParameter("Items");
        response.setContentType("text/vnd.wap.wml");
        PrintWriter out = response.getWriter();
        out.println("<?xml version=/"1.0/"?>");
        out.println("<!DOCTYPE wml PUBLIC/"-//WAPFORUM//DTD WML 1.1//EN/"");
        out.println("/"http://www.wapforum.org/DTD/wml_1.1.xml/">");
        out.println("<wml>");
        out.println("<card title=/"test/">");
        out.println(" <p align=/"center/">");
        out.println("you selected "+select);
        out.println("</p>");
        out.println("</card>");
        out.println("</wml>");

    }

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {
        doGet(request,response);
    }
}