Ajax二级联动菜单实现原理及代码

2019-09-14 07:14:41王旭

</div>
</body>
</html>

SelectServlet:

package com;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/***
*
* @author zdw
*
*/
public class SelectServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
public SelectServlet()
{
super();
}
public void destroy()
{
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// response.setCharacterEncoding("GBK");
response.setContentType("text/xml");
response.setHeader("Cache-Control", "no-cache");
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("UTF-8");
String targetId = request.getParameter("id").toString();
System.out.println(targetId);
// 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>请选择</text></select>";
} else if (targetId.equalsIgnoreCase("1"))
{
xml = "<select><value>1</value><text>昌平</text></select>";
xml += "<select><value>2</value><text>丰台</text></select>";
xml += "<select><value>3</value><text>海淀</text></select>";
xml += "<select><value>4</value><text>朝阳</text></select>";
} else if (targetId.equalsIgnoreCase("2"))
{
xml = "<select><value>1</value><text>塘沽区</text></select>";
xml += "<select><value>2</value><text>汉沽区</text></select>";
xml += "<select><value>3</value><text>大港区</text></select>";
xml += "<select><value>4</value><text>东丽区</text></select>";
} else
{// 如果是3,则返回下面的字符
xml = "<select><value>1</value><text>济南</text></select>";
xml += "<select><value>2</value><text>青岛</text></select>";
xml += "<select><value>3</value><text>淄博</text></select>";
xml += "<select><value>4</value><text>枣庄</text></select>";
}
String last_xml = xml_start + xml + xml_end;
response.getWriter().write(last_xml);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
doGet(request, response);
}
public void init() throws ServletException
{
}
}