• Servlet+Ajax实现搜索智能提示及遇到的问题


    Servlet+Ajax实现搜索智能提示的案例网上很多,先贴上自己使用的代码。

    index.jsp

    <%@ 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>smart search</title>
    <style type="text/css">
    .mouseOver {
        background: #00B2EE;
        color: white;
         200px;
    }
    .mouseOut {
        background: #EDEDED;
         200px;
    }
    </style>
    <script type="text/javascript">
            var xmlHttp;
        //获取用户输入的关联信息的函数
        function getMoreContens() {
            //获取用户输入
            var content = document.getElementById("keyWords").value;
            if (content == "") {
                clearContent();
                return;
            }
            xmlHttp = createXmlHttp();
            //给服务器发送数据
            var url = "search?keyword="+encodeURI(content); 
            xmlHttp.open("GET",url,true);
            xmlHttp.onreadystatechange =     //回调函数
                function callback()
            {
                if(xmlHttp.readyState == 4)
                    {
                    if(xmlHttp.status == 200){
                        var result = decodeURIComponent(xmlHttp.responseText);
                        var json = eval("("+result+")");
                        clearContent(json);
                        intelliSense(json);
                    }
                    }
            };
            /*
                xmlhttp的send是传递参数用的,但是只有在使用post方式提交请求的时候才有用
                如下:
                xmlhttp.open("post",url,true); 
                ...
                xmlhttp.send("data=data&data2=data2");
                 
                用get的话一般就是:
                xmlhttp.open("get",url,true); 
                ...
                xmlhttp.send(null);
            */
            xmlHttp.send(null);
        }
        
        //创建XMLHttpRequest
        function createXmlHttp()
        {
            var xmlHttp;
            if(window.XMLHttpRequest)
                {
                xmlHttp = new XMLHttpRequest();
                //兼容某些Mozilla浏览器的响应头,强制设置为text/xml,具体参看:http://www.cnblogs.com/perseverancevictory/p/3690769.html
                   if(xmlHttp.overrideMimeType){  
                       xmlHttp.overrideMimeType("text/xml");
                   }
                }
            //兼容IE
            else if(window.ActiveXObject)
                {
                xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
                if(!xmlHttp)
                    {
                    xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
                    }
                }
            return xmlHttp;
        }
    
        function clearContent()
        {
            var contentTableBody = document.getElementById("content_table_body");
            var size = contentTableBody.childNodes.length;
            for(var i=size-1;i>0;i--)
                {
                contentTableBody.removeChild(contentTableBody.childNodes[i]);
                }
        }
        function intelliSense(json)
        {
            //获取关联数据的长度
            var size = json.length;
            for(var i=0;i<size;i++)
                {
                var nextNode = json[i];
                var tr= document.createElement("tr");
                var td= document.createElement("td");
                tr.setAttribute("border", "0");
                tr.setAttribute("bgcolor", "#EDEDED");
                td.setAttribute("width", "200px");
                td.onmouseover=function()
                {
                    this.className = 'mouseOver';
                }
                td.onmouseout=function()
                {
                    this.className = 'mouseOut';
                }
                td.onclick=function()
                {
                    document.getElementById("keyWords").value=this.innerText;
                }
                var text=document.createTextNode(nextNode);
                td.appendChild(text);
                tr.appendChild(td);
                document.getElementById("content_table_body").appendChild(tr);
                }
        }
    </script>
    </head>
    <body>
        <div>
            <input type="text"  name="keyWords" id="keyWords"  style="200px; height:20px;" onkeyup="getMoreContens()" onfocus="getMoreContens()" onblur="clearContent()" /> <input
                type="button" id="button" value="百度一下">
                <div id="popDiv">
                <table id="content_table">
                    <tbody id="content_table_body">
                    </tbody>
                </table>
            </div>
        </div>
    </body>
    </html>
    

      web.xml

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app id="WebApp_ID" version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <servlet-mapping>
        <servlet-name>search</servlet-name>
        <url-pattern>/search</url-pattern>
    </servlet-mapping>
    <servlet>
        <description>搜索</description>
        <servlet-name>search</servlet-name>
        <servlet-class>com.baorant.search.SearchServlet</servlet-class>
    </servlet> 
    </web-app>
    

      SearchServlet类

    package com.baorant.search;
    
    import java.io.IOException;
    import java.net.URLEncoder;
    import java.util.ArrayList;
    import java.util.List;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.alibaba.fastjson.JSON;
    
    public class SearchServlet extends HttpServlet {
    
        private static List<String> keyWordList = new ArrayList<String>();
        static {
            // 模拟数据
            keyWordList.add("yanwei");
            keyWordList.add("yantian");
            keyWordList.add("yanpeng");
            keyWordList.add("yanweichao");
            keyWordList.add("yanweiqi");
            keyWordList.add("yanyurong");
            keyWordList.add("yanmeirong");
            keyWordList.add("yanweichen");
            keyWordList.add("电影");
            keyWordList.add("电影 66ys");
        }
        private static final long serialVersionUID = 1L;
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
            doGet(req, resp);
        }
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
    
            String keyWord = req.getParameter("keyword");
            System.out.println(keyWord);
            List<String> list = keyWord==null?new ArrayList<String>():getDatas(keyWord);
            String json = JSON.toJSONString(list);
            //防止乱码
            String encodeJSON = URLEncoder.encode(json,"UTF-8");
            resp.getWriter().write(encodeJSON);
        }
    
        public static List<String> getDatas(String keyWord) {
            List<String> list = new ArrayList<String>();
            for (int i = 0; i < keyWordList.size(); i++) {
                if (keyWordList.get(i).contains(keyWord)) {
                    list.add(keyWordList.get(i));
                }
            }
            return list;
        }
    }
    

      已直接从工程build path导入fastjson-1.2.2.jar,但仍然报错:java.lang.ClassNotFoundException: com.alibaba.fastjson.JSON

    解决方法:将之前直接导入的jar包复制放入项目中lib目录下,重新编译,成功

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  • 原文地址:https://www.cnblogs.com/baorantHome/p/9065538.html
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