AJAX - $.get( url, [data], [success], [type] )

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$.get(url,data,success(response,status,xhr),dataType)

url：必需。规定将请求发送的哪个 URL。

data：可选。规定连同请求发送到服务器的数据。

success(response,status,xhr)：可选。规定当请求成功时运行的函数。

额外的参数：

response - 包含来自请求的结果数据

status - 包含请求的状态

xhr - 包含 XMLHttpRequest 对象
dataType：可选。规定预计的服务器响应的数据类型。

默认地，jQuery 将智能判断。

可能的类型：”xml”“html”“text”“script”“json”“jsonp”

【JSP页面】

<%@ 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 HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">    <title>My JSP 'post.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">    <meta http-equiv="cache-control" content="no-cache">    <meta http-equiv="expires" content="0">        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    <meta http-equiv="description" content="This is my page">    <!--    <link rel="stylesheet" type="text/css" href="styles.css">    -->    <script type="text/javascript" src="./scripts/jquery-1.7.2.js"></script>    <script type="text/javascript">        var url ="";        var queryString = "";        $(function(){            $("input[type='button']").click(function(){                url = $("#editform").attr("action");                queryString = $('#editform').serialize();                $.get(url+"?querystring="+queryString,queryString,function(data){//querystring=username=yanshi02&password=123456&username=yanshi02&password=123456//resultJson ...{"username":"yanshi02","querystring":"username=yanshi02","password":"123456"}                //$.get(url+"?querystring="+queryString,function(data){                //querystring=username=yanshi02&password=123456                //resultJson ...{"querystring":"username=yanshi02","password":"123456"}                //$.get(url,queryString,function(data){                //username=yanshi02&password=123456                //resultJson ...{"username":"yanshi02","password":"123456"}                    alert(data);                }                ,"json");            });        });    </script>  </head>  <body>    This is my JSP page. <br>    <form id="editform" action="postServlet2" method="get">        <input type="text" name="username" value=""/>        <input type="password" name="password" value=""/>    </form>    <input name="post" type="button" value="提交"/>  </body></html>

如下图标明：

get方式数据都在Query String Parameters里面！！！

这里写图片描述

【后台接收思路】：

讲post的时候已经说明，request.getReader()只能获取请求体(form data)的数据，URL的数据(query string)获取不到！

① 使用request.getParameterMap;

该方法不分Form Data or Query String Parameters , 而是将数据以Map<String,String[]>返回。同名称的key对应的值，组成一个String[ ];

参考前篇post 的后台接收方法2：后台接收方法2
http://blog.csdn.net/j080624/article/details/54946974

② 使用request.getQueryString;

package com.atgui.ajax.app.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.codehaus.jackson.map.ObjectMapper;public class GetServlet extends HttpServlet {    /**     * Destruction of the servlet. <br>     */    public void destroy() {        super.destroy(); // Just puts "destroy" string in log        // Put your code here    }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        doPost(request, response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html");        PrintWriter out = response.getWriter();        //拿到$("#editform").serialize();        String jsonString =request.getQueryString() ;        System.out.println(jsonString);        //通过拿到的querystring转换为map        HashMap<String, Object> map = getMapFromQueryString(jsonString);        //将转换得到的map转换为json并返回        ObjectMapper objectMapper = new ObjectMapper();        String resultJson = objectMapper.writeValueAsString(map);        System.out.println("resultJson ..."+resultJson);        out.print(resultJson);        out.flush();        out.close();    }    public void init() throws ServletException {        // Put your code here        System.out.println("getServlet init()....");    }    public HashMap<String, Object> getMapFromQueryString(String queryString) {        //这个方法可能不适用你        HashMap map = new HashMap<String, String>();        String[] qStrings = queryString.split("&");        for (String string : qStrings) {            String[] qStrings2 = string.split("=");            map.put(qStrings2[0], qStrings2[1]);        }        return map;    }}

result as follows ：

getServlet init()....username=yanshi02&password=123456resultJson ...{"username":"yanshi02","password":"123456"}

此时的json为typeof data = object 可以直接使用data.key 获取属性，不用进行转换！！！

题外话

上面所传输的数据格式为username=yanshi02&password=123456。

如果传输的数据为JSON形式呢？

queryString = $('#editform').serializeArray();//objectqueryString = JSON.stringify(queryString);//string

请看下一篇JSON形式【http://blog.csdn.net/J080624/article/details/54949773】

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