/**
*SelectServelet.java 处理页面返回的数据,返回XML给AJAX使用
*
*/

[java]
package onlinetest.servlet;

import java.io.IOException;

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

public class SelectServlet extends HttpServlet {

  /**
   * The doGet method of the servlet. <br>
   *
   * This method is called when a form has its tag value method equals to get.
   *
   * @param request
   *            the request send by the client to the server
   * @param response
   *            the response send by the server to the client
   * @throws ServletException
   *             if an error occurred
   * @throws IOException
   *             if an error occurred
   */
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    response.setContentType("text/xml");
    response.setHeader("Cache-Control", "no-cache");
    String targetId = request.getParameter("id").toString();
    // 获得请求中参数为id的值
    String xml_start = "<selects>";
    String xml_end = "</selects>";
    String xml = "";

    if (targetId.equalsIgnoreCase("0")) {
      xml = "<select><value>0</value><text>Unbounded</text></select>";
    } else if (targetId.equalsIgnoreCase("1")) {
      xml = "<select><value>1</value><text>Mana Burn</text></select>";
      xml += "<select><value>2</value><text>Death Coil</text></select>";
      xml += "<select><value>3</value><text>Unhkly Aura</text></select>";
      xml += "<select><value>4</value><text>Unholy Fire</text></select>";
    } else if (targetId.equalsIgnoreCase("2")) {
      xml = "<select><value>1</value><text>Corpexplode</text></select>";
      xml += "<select><value>2</value><text>Raise Dead</text></select>";
      xml += "<select><value>3</value><text>Brilliance Aura</text></select>";
      xml += "<select><value>4</value><text>Aim Aura</text></select>";
    } else {// 如果是3,则返回下面的字符
      xml = "<select><value>1</value><text>Rain of Chaos</text></select>";
      xml += "<select><value>2</value><text>Finger of Death</text></select>";
      xml += "<select><value>3</value><text>Bash</text></select>";
      xml += "<select><value>4</value><text>Summon Doom</text></select>";
    }

    String last_xml = xml_start + xml + xml_end;
    response.getWriter().write(last_xml);

  }

  /**
   * The doPost method of the servlet. <br>
   *
   * This method is called when a form has its tag value method equals to
   * post.
   *
   * @param request
   *            the request send by the client to the server
   * @param response
   *            the response send by the server to the client
   * @throws ServletException
   *             if an error occurred
   * @throws IOException
   *             if an error occurred
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    doGet(request, response);// 对于post的请求方式和get请求方式一样处理
  }

}
[/java]

/**
*web.xml 配置Servlet,可以使用MyEclipse创建Servlet,自动生成web.xml
*
*/

[xml]
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="<a href="http://java.sun.com/xml/ns/j2ee"" target="_blank">[url]http://java.sun.com/xml/ns/j2ee[/url]"</a> xmlns:xsi="<a href="http://www.w3.org/2001/XMLSchema-instance"" target="_blank">[url]http://www.w3.org/2001/XMLSchema-instance[/url]"</a> version="2.4" xsi:schemaLocation="<a href="http://java.sun.com/xml/ns/j2ee" target="_blank">[url]http://java.sun.com/xml/ns/j2ee[/url]</a>   <a href="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">" target="_blank">[url]http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd[/url]"></a>
  <servlet>
    <servlet-name>select</servlet-name>
    <servlet-class>onlinetest.servlet.SelectServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>select</servlet-name>
    <url-pattern>/servlet/select</url-pattern>
  </servlet-mapping>
  
  <filter>
        <filter-name>characterFilter</filter-name>
        <filter-class>filters.SetCharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
   <filter-mapping>
    <filter-name>characterFilter</filter-name>
    <url-pattern>/*</url-pattern>
   </filter-mapping>
</web-app>[/xml]

原文地址:[url]http://my.boolean.cn/read.php?130&part=3[/url]