Prototype的Ajax支持应用Ajax.Request类 _Ajax

Prototype的Ajax支持使用Ajax.Request类

我们只要简单的创建一个Ajax.Request对象，就可以完成异步请求的放送

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
		<title>输入提示示范</title>
		<meta name="author" content="Yeeku.H.Lee" />
		<meta name="website" content="http://www.crazyit.org" />
		<meta http-equiv="Content-Type" content="text/html; charset=GBK" />
	</head>
	<body>
		<h3>
			请输入您喜欢的水果
		</h3>
		<div style="width: 280px; font-size: 9pt">
			输入apple、banana、peach可看到明显效果:
		</div>
		<br />
		<!-- 当鼠标移开的时候执行hide方法，隐藏起来 -->
		<input id="favorite" name="favorite" type="text"
			onblur="$('tips').hide();" />
		<div id="tips"
			style="width: 160px; border: 1px solid menu; background-color: #ffffcc; display: none"></div>
			
		<script src="js/prototype-1.6.0.3.js" type="text/javascript"></script>
		<script type="text/javascript">
			//监控目标文本框输入文字发生改变的函数
			function searchFruit() {
				//请求的地址
				var url = 'TipServlet';
				//将favorite表单域的值转换为请求参数
				var params = Form.Element.serialize('favorite');
				//创建Ajax.Request对象，对应于发送请求
				var myAjax = new Ajax.Request(url, {
					//请求方式：POST
					method : 'post',
					//请求参数
					parameters : params,
					//指定回调函数
					onComplete : showResponse,
					//是否异步发送请求
					asynchronous : true
				});
			}
			//定义回调函数
			function showResponse(request) {
				//在提示tip元素中输出服务器的响应
				$('tips').innerHTML = request.responseText;
				//显示提示tip对象
				$('tips').show();
			}
			//为favorite表单域绑定事件处理函数
			new Form.Element.Observer("favorite", 0.5, searchFruit);
		</script>
	</body>
</html>

?请求的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;


public class TipServlet extends HttpServlet {

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

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		//获取请求参数favorite
		String hdchar = request.getParameter("favorite");
		System.out.println(hdchar);
		PrintWriter out = response.getWriter();
		//如果请求参数是apple的前几个字符，则输出apple
		if ("apple".startsWith(hdchar))
		{
			out.println("apple");
		}
		//如果请求参数是banana的前几个字符，则输出banana
		else if("banana".startsWith(hdchar))
		{
			out.println("banana");
		}
		//如果请求参数是peach的前几个字符，则输出peach
		else if("peach".startsWith(hdchar))
		{
			out.println("peach");
		}
		//否则将输出other fruit
		else
		{
			out.println("other fruit");
		}
	}

}