Jquery+ajax+JAVA(servlet)实现下拉菜单异步取值

首先来看工程结构图：

项目所需要的包，如下所示：

JSP代码：

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
      System.out.println("basePath="+basePath);
%>









  

    
    
      点击取值
    
  
  
    
记录信息：
    
  

JAVA servlet代码：

package servlet;

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;
import net.sf.json.JSONArray;

public class ValueGetController extends HttpServlet {
  
  private static final long serialVersionUID = -1293610555518403602L;


  /**
   * Constructor of the object.
   */
  public ValueGetController() {
    super();
  }

  /**
   * Destruction of the servlet. 

   */
  public void destroy() {
    super.destroy(); // Just puts "destroy" string in log
    // Put your code here
  }

  /**
   * The doGet method of the servlet. 

   *
   * 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 {

    doPost(request, response);
    

  }

  /**
   * The doPost method of the servlet. 

   *
   * 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 {

    request.setCharacterEncoding("GBK");
     response.setContentType("text/html;charset=gbk");
     PrintWriter out = response.getWriter();
     String action = request.getParameter("action");
     System.out.println("action"+action);
     if (action.equals("GetFirstFloorValue")) {
             String[] str = GetFirstFloorValue();
             JSONArray ja = JSONArray.fromObject(str);
             String json = ja.toString();
              out.print(json);
             System.out.println(json);
             out.flush();
              out.close();
              return;
           }
            out.flush();
            out.close();
  }

  private String[] GetFirstFloorValue() {
     String[] str = new String[4];
         str[0] = "test1";
         str[1] = "test2";
         str[2] = "test3";
         str[3] = "test4";
         return str;

  }

  

}

关于servlet的web.xml配置：

 
  This is the description of my J2EE component
  This is the display name of my J2EE component
  ValueGetController
  servlet.ValueGetController
 

 
  ValueGetController
  /ValueGetController
 
 
 
  
 
  index.jsp
 

以上就是本文的全部内容，希望对大家的学习有所帮助。