JSON(JavaScript Object Notation) 是一種輕量級(jí)的數(shù)據(jù)交換格式。它基于ECMAScript的一個(gè)子集。 JSON采用完全獨(dú)立于語(yǔ)言的文本格式,但是也使用了類似于C語(yǔ)言家族的習(xí)慣(包括C、C++、C#、Java、JavaScript、Perl、Python等)。這些特性使JSON成為理想的數(shù)據(jù)交換語(yǔ)言。 易于人閱讀和編寫,同時(shí)也易于機(jī)器解析和生成(一般用于提升網(wǎng)絡(luò)傳輸速率)。
json簡(jiǎn)單說(shuō)就是javascript中的對(duì)象和數(shù)組,所以這兩種結(jié)構(gòu)就是對(duì)象和數(shù)組兩種結(jié)構(gòu),通過(guò)這兩種結(jié)構(gòu)可以表示各種復(fù)雜的結(jié)構(gòu)。
1、對(duì)象:對(duì)象在js中表示為“{}”括起來(lái)的內(nèi)容,數(shù)據(jù)結(jié)構(gòu)為 {key:value,key:value,...}的鍵值對(duì)的結(jié)構(gòu),在面向?qū)ο蟮恼Z(yǔ)言中,key為對(duì)象的屬性,value為對(duì)應(yīng)的屬性值,所以很容易理解,取值方法為 對(duì)象.key 獲取屬性值,這個(gè)屬性值的類型可以是 數(shù)字、字符串、數(shù)組、對(duì)象幾種。
2、數(shù)組:數(shù)組在js中是中括號(hào)“[]”括起來(lái)的內(nèi)容,數(shù)據(jù)結(jié)構(gòu)為 ["java","javascript","vb",...],取值方式和所有語(yǔ)言中一樣,使用索引獲取,字段值的類型可以是 數(shù)字、字符串、數(shù)組、對(duì)象幾種。
經(jīng)過(guò)對(duì)象、數(shù)組2種結(jié)構(gòu)就可以組合成復(fù)雜的數(shù)據(jù)結(jié)構(gòu)了。
使用JSON前需要先的導(dǎo)入json.jar包
傳輸單個(gè)對(duì)象:
新建一個(gè) servlet
package com.itnba.maya.a; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.json.JSONObject; /** * Servlet implementation class C */ @WebServlet("/C") public class C extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public C() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); //模擬從數(shù)據(jù)庫(kù)中查處 Dog a=new Dog(); a.setName("小黃"); a.setAge(5); a.setZl("哈士奇"); JSONObject obj=new JSONObject(); obj.put("name", a.getName()); obj.put("age", a.getAge()); obj.put("zl", a.getZl()); JSONObject bb=new JSONObject(); bb.put("obj", obj); response.getWriter().append(bb.toString()); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
效果如下:
jsp頁(yè)面
<%@ 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>Insert title here</title> <script type="text/javascript" src="js/jquery-1.11.1.min.js"></script> <script type="text/javascript"> $(document).ready(function(){ $("#k").click(function(){ $.ajax({ url:"C", data:{}, type:"POST", dataType:"JSON", success:function(httpdata){ $("#x").append("<li>"+httpdata.obj.name+"</li>"); $("#x").append("<li>"+httpdata.obj.age+"</li>"); $("#x").append("<li>"+httpdata.obj.zl+"</li>") } }) }); }); </script> </head> <body> <span id="k">查看</span> <h1> <ul id="x"> </ul></h1> </body> </html>
效果如下:
傳輸集合或數(shù)組:
servlet:
package com.itnba.maya.a; import java.io.IOException; import java.util.ArrayList; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.json.JSONArray; import org.json.JSONObject; /** * Servlet implementation class D */ @WebServlet("/D") public class D extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public D() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); //模擬從數(shù)據(jù)庫(kù)中查出 Dog a1=new Dog(); a1.setName("小黃"); a1.setAge(5); a1.setZl("哈士奇"); Dog a2=new Dog(); a2.setName("中黃"); a2.setAge(6); a2.setZl("泰迪"); Dog a3=new Dog(); a3.setName("大黃"); a3.setAge(7); a3.setZl("京巴"); ArrayList<Dog> list=new ArrayList<Dog>(); list.add(a1); list.add(a2); list.add(a3); JSONArray arr= new JSONArray(); //遍歷集合 for(Dog d:list){ JSONObject obj=new JSONObject(); obj.put("name", d.getName()); obj.put("age", d.getAge()); obj.put("zl", d.getZl()); arr.put(obj); } response.getWriter().append(arr.toString()); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
效果如下:
jsp頁(yè)面:
<%@ 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>Insert title here</title> <script type="text/javascript" src="js/jquery-1.11.1.min.js"></script> <script type="text/javascript"> $(document).ready(function(){ $("#k").click(function(){ $.ajax({ url:"D", data:{}, type:"POST", dataType:"JSON", success:function(httpdata){ for(var i=0;i<httpdata.length;i++){ var n=httpdata[i].name var a=httpdata[i].age var z=httpdata[i].zl var tr="<tr>" tr+="<td>"+n+"</td>" tr+="<td>"+a+"</td>" tr+="<td>"+z+"</td>" tr+="</tr>" $("#x").append(tr) } } }) }); }); </script> </head> <body> <span id="k">查看</span> <h1> <table width="100%" id="x" border="1px"> </table> </h1> </body> </html>
效果如下:
相信看了本文案例你已經(jīng)掌握了方法,更多精彩請(qǐng)關(guān)注Gxl網(wǎng)其它相關(guān)文章!
推薦閱讀:
Ajax直接實(shí)現(xiàn)點(diǎn)贊功能步奏詳解
前端與后端有哪幾種ajax交互方法
聲明:本網(wǎng)頁(yè)內(nèi)容旨在傳播知識(shí),若有侵權(quán)等問(wèn)題請(qǐng)及時(shí)與本網(wǎng)聯(lián)系,我們將在第一時(shí)間刪除處理。TEL:177 7030 7066 E-MAIL:11247931@qq.com