使用Ajax以及CSS+DIV高仿谷歌搜索（附源码下载） .

来源：互联网发布：java 线程通信编辑：程序博客网时间：2024/06/06 12:41

在使用Google搜索或者是Baidu搜索的时候，在输入搜索关键字的同时，会自动弹出匹配的其他关键字的提示，全心全意为人民服务的精神在这里崭露无遗。这种利用Ajax技术实现输入提示和自动完成的功能是Google率先推出的，然后在其他的Web应用中被广泛的应用。利用Ajax实现部分页面刷新或者自动完成会使得用户体验绝大大提升。

技术永远是为用户服务的（无论是性能方面还是美观方面），脱离了用户就没有技术的发展，或者说只有用户才能促进技术的进步。

在掌握了Ajax原理之后我们也可以模仿谷歌，来实现一个搜索引擎的小Demo。

在实现的过程中主要运用的是Ajax技术，CSS+DIV布局，Servlet+JavaBean，还有数据库的基本知识等等。下面大致的描述一下实现的步骤，请大家跟随文字来共同完成我们的Google。有兴趣的朋友可以点击这里下载源码（实现仓促，如有不足之处请谅解）

1、准备后台以及数据库，完成数据库（MySql）操作部分。

这里很简单，首先编写ConnectionManager类，来实现对数据库的连接、查询功能。

代码如下：

[java] view plaincopyprint?

package com.ncs.common;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ConnectionManager {
private static String URL="jdbc:mysql://localhost:3306/test";
private static String DRIVER="com.mysql.jdbc.Driver";
private static String USER="root";
private static String PASSWORD="123456";
private static Connection conn=null;
private static Statement stmt=null;
private static ResultSet rs=null;
public static void getConnection(){
try {
Class.forName(DRIVER);
try {
conn = DriverManager.getConnection(URL, USER, PASSWORD);
System.out.println("Successfully connected to Mysql DB!");
} catch (SQLException e) {
System.out.println("Connection DB failed!");
}
} catch (ClassNotFoundException e) {
System.out.println("Driver:"+DRIVER+" can't find!");
}
}
public static void closeConnection(){
try {
conn.close();
conn=null;
} catch (SQLException e) {
e.printStackTrace();
}
}
public static ResultSet executeQuery(String sql){
try {
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
return rs;
} catch (SQLException e) {
return null;
}
}
public static void main(String[] args) {
//getConnection();
}
}

package com.ncs.common;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class ConnectionManager {private static String URL="jdbc:mysql://localhost:3306/test";private static String DRIVER="com.mysql.jdbc.Driver";private static String USER="root";private static String PASSWORD="123456";private static Connection conn=null;private static Statement stmt=null;private static ResultSet rs=null;public static void getConnection(){try {Class.forName(DRIVER);try {conn = DriverManager.getConnection(URL, USER, PASSWORD);System.out.println("Successfully connected to Mysql DB!");} catch (SQLException e) {System.out.println("Connection DB failed!");}} catch (ClassNotFoundException e) {System.out.println("Driver:"+DRIVER+" can't find!");}}public static void closeConnection(){try {conn.close();conn=null;} catch (SQLException e) {e.printStackTrace();}}public static  ResultSet executeQuery(String sql){try {stmt=conn.createStatement();rs=stmt.executeQuery(sql);return rs;} catch (SQLException e) {return null;}}public static void main(String[] args) {//getConnection();}}

2、编写页面

在页面中添加必须要有的文本框，以及两个按钮。其中必不可少的是在文本框输入文本时才出现的一个隐藏DIV。

代码如下：

[html] view plaincopyprint?

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>Google</title>
<%
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragrma","no-cache");
response.setDateHeader("Expires",0);
%>
<link type="text/css" href="css/autoComplete.css" rel="stylesheet"/>
<script type="text/javascript" src="scripts/autoComplete.js"></script>
</head>
<body onload="setPosition($('txtKeyword'))">
<div id="img"><img src="images/google.jpg"></img></div>
<form id="form1">
<div id="input"><input type="text" onkeydown="if(GetKeyCode(event)==13)form_submit()" onkeyup="GetSuggest(this.value,event);updown(event)" autocomplete="off" id="txtKeyword" />
</div>
<div id="dSuggest"></div>
<div id="button">
<input id="submit" type="submit" value="Google 搜索" onclick="alert('Now Search ...')" />
<input id="submit" type="submit" value="手气不错" onclick="alert('Now Search ...')" />
</div>
</form>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!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>Google</title>    <%    response.setHeader("Cache-Control","no-store");     response.setHeader("Pragrma","no-cache");     response.setDateHeader("Expires",0);     %>    <link type="text/css" href="css/autoComplete.css" rel="stylesheet"/>    <script type="text/javascript" src="scripts/autoComplete.js"></script></head><body onload="setPosition($('txtKeyword'))"><div id="img"><img src="images/google.jpg"></img></div>    <form id="form1">    <div id="input"><input type="text" onkeydown="if(GetKeyCode(event)==13)form_submit()" onkeyup="GetSuggest(this.value,event);updown(event)" autocomplete="off" id="txtKeyword" />    </div>    <div id="dSuggest"></div>    <div id="button">    <input id="submit" type="submit"  value="Google 搜索" onclick="alert('Now Search ...')" />     <input id="submit" type="submit"  value="手气不错" onclick="alert('Now Search ...')" />    </div>    </form></body></html>

3、实现Servlet

编写Servlet来实现将页面的数据拼成Sql语句并传到ConnectionManager类，将返回的结果输出的页面。（需要注意的是，这里我们采用得是直接输出jsp代码，所以要为DIV加上id属性以便在CSS中控制样式，以及相关事件以便于在js中控制效果。）

代码如下：

[java] view plaincopyprint?

package com.ncs.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ncs.common.ConnectionManager;
public class suggest extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
// resp.setContentType("text/xml;charset=utf-8");
System.out.println("Enter Servlet Get Method..");
PrintWriter out=resp.getWriter();
String param=(String)req.getParameter("id");
String paramValue=param.trim().length()>0?param.trim():"unknown";
String sql="select name from tbl_ajax_search where name like '"+paramValue+"%'";
System.out.println("sql="+sql);
ConnectionManager.getConnection();
ResultSet rs=ConnectionManager.executeQuery(sql);
StringBuffer sb=new StringBuffer();
//sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>")
// .append("<data>");
sb.append("<ul id=\"sug\">");
int pos=0;
try {
while(rs.next()){
System.out.println("pos="+pos);
sb.append("<li onclick=\"form_submit()\" onmouseover=\"myMouseOver(")
.append(pos)
.append(");\" onmouseOut=\"myMouseOut(")
.append(pos)
.append(");\">")
.append(rs.getString(1)+"</li>");
//sb.append("<item>")
//.append(rs.getString(1))
// .append("</item>");
pos++;
}
sb.append("</ul>");
int posi = sb.toString().indexOf("onmouseover");
System.out.println("posi="+posi);
if(posi==-1){
System.out.println("no content found.");
out.write("");
}else{
System.out.println(sb.toString());
out.write(sb.toString());
}
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(req,resp);
}
}

package com.ncs.servlet;import java.io.IOException;import java.io.PrintWriter;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.ncs.common.ConnectionManager;public class suggest extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {req.setCharacterEncoding("UTF-8");//resp.setContentType("text/xml;charset=utf-8");System.out.println("Enter Servlet Get Method..");PrintWriter out=resp.getWriter();String param=(String)req.getParameter("id");String paramValue=param.trim().length()>0?param.trim():"unknown";String sql="select name from tbl_ajax_search where name like '"+paramValue+"%'";System.out.println("sql="+sql);ConnectionManager.getConnection();ResultSet rs=ConnectionManager.executeQuery(sql);StringBuffer sb=new StringBuffer();//sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>") // .append("<data>");sb.append("<ul id=\"sug\">");int pos=0;try {while(rs.next()){System.out.println("pos="+pos);sb.append("<li onclick=\"form_submit()\" onmouseover=\"myMouseOver(").append(pos).append(");\" onmouseOut=\"myMouseOut(").append(pos).append(");\">").append(rs.getString(1)+"</li>");//sb.append("<item>")  //.append(rs.getString(1)) // .append("</item>");pos++;}sb.append("</ul>");int posi = sb.toString().indexOf("onmouseover");System.out.println("posi="+posi);if(posi==-1){System.out.println("no content found.");out.write("");}else{System.out.println(sb.toString());out.write(sb.toString());}} catch (SQLException e) {e.printStackTrace();}}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {// TODO Auto-generated method stubdoGet(req,resp);}}

4、仿照Google调整页面的布局

这里重点就是调整隐藏的DIV以及按钮的样式。

最终效果如下图

后记：关于模仿

自呱呱坠地我们就开始了自己一生的学习，在学习的过程中有着必不缺少的一个步骤：模仿。我们的学习大多是从模仿开始的，无论是模仿父母的声音牙牙学语，还是模仿大人走路的姿势蹒跚学步；无论是模仿书本上的文字一笔一画，还是模仿课文的结构字斟句酌。这都是开始学习的第一个过程——模仿。当然随着模仿的深入我们掌握了原理就可以开始下一个阶段的学习：使用和发挥。使用和发挥有赖于模仿的功力，只有初期模仿的到位，模仿的逼真，才能有后期的漂亮运用与灵活发挥。

我们的学习之路：模仿——使用——发挥