%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
 head>
  meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  title>Test Baidu/title>
 /head>
 body>
 	!--
  	文本输入框
  -->
 	div id="serach">
 		input type="text" name="text" id="text" />
 		input type="submit" value="搜索" />
 	/div>
 	
 	!--
  	提示下拉框
  -->
  div id="tips" style="display: none; 
  	width: 171px; border: 1px solid pink";>
  /div>
  
 	/body>
 	script>
 		window.onload=function(){
 			//获取文本输入框
 			var textElment = document.getElementById("text");
 			//获取下提示框
 			var div = document.getElementById("tips");
 			textElment.onkeyup=function(){
 				//获取用户输入的值
 				var text = textElment.value;
 				//如果文本框中没有值，则下拉框被隐藏，不显示
 				if(text==""){
 					div.style.display="none";
 					return;
 				}
 				//获取XMLHttpRequest对象
 				var xhr = new XMLHttpRequest();
 				//编写回调函数
 				xhr.onreadystatechange=function(){
 					//判断回调的条件是否准备齐全
 					if(xhr.readyState==4){
 						if(xhr.status==200){
 							//取的服务器端传回的数据
 							var str = xhr.responseText;
 							
 							//判断传回的数据是否为空,若是则直接返回，不显示
 							if(str==""){
 								return;
 							}
 							//我们将会在服务器端把数据用 , 隔开，当然这里也可以使用json
 							var result = str.split(",");
 							var childs = "";
 							//遍历结果集，将结果集中的每一条数据用一个div显示，把所有的div放入到childs中
 							for(var i=0; iresult.length;i++){
 								childs += "div onclick='Write(this)' onmouseout='recoverColorwhenMouseout(this)' onmouseover='changeColorwhenMouseover(this)'>"+result[i]+"/div>";
 							}
 							//把childs 这div集合放入到下拉提示框的父div中，上面我们以获取了
 							div.innerHTML=childs;
 							div.style.display="block";
 						
 						}
 					}
 				}
 			
 				//创建与服务器的连接
 				xhr.open("GET","${pageContext.request.contextPath}/test?text="+text);
 			
 
 				//发送
 				xhr.send();
 			}
 		}
 		//鼠标悬停时改变div的颜色
 		function changeColorwhenMouseover(div){
 			div.style.backgroundColor="pink";
 		}
 		//鼠标移出时回复div颜色
 		function recoverColorwhenMouseout(div){
 			div.style.backgroundColor="";
 		}
 		//当鼠标带点击div时，将div的值赋给输入文本框
 		function Write(div){
 			//将div中的值赋给文本框
 			document.getElementById("text").value=div.innerHTML;
 			
 			//让下拉提示框消失
 			
 			div.parentNode.style.display="none";
 		}
 	/script>
/html>

package com.zhuxingyi.servlet;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * 百度下拉框服务器端
 */
@WebServlet("/test")
public class test extends HttpServlet {
	private static final long serialVersionUID = 1L;
 
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获取前端传入的数据
		String text = request.getParameter("text");
		//我们在这里也还是向list集合中添加数据，模拟数据库的查询操作
		System.out.println(text);
		ListString> list =new ArrayList>();
		list.add("zhuxingyi");
		list.add("zhuwei");
		list.add("zhuyuanz");
		list.add("zhude");
		
		//将数据 转换成字符串
		String str = "";
		if(text.startsWith("z")) {
			for(int i=0;ilist.size();i++) {
				if(i>0) {
					str+=",";
				}
				str+=list.get(i);
			}
			//将处理好的数据传回给客户端
			response.getWriter().write(str);
		}
		
	}
 
 
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
 
}