양군이 놀이터

1 문서 개요 #

• 작성일 : 2006/04/04
  
• 작성자 :
  
• 문서 내용 : AJAX XMLHTTPREQUEST에서 데이터 교환 형식으로 사용되는 JSON에 대한 정리
  

2 개요 #

• Javascript Object Notation.
  
• lightweight data 교환 형식.
  
• 사람이 읽고 쓰기 쉬움.
  
• 기계가 파싱하고 생성하기 쉬움.
  
• 
  

3 형식 #

3.1 Object #

• 중괄호({})로 시작하고 끝남
  
• member : 문자열과 값으로 구성되어 있고 콜론(:)으로 구분, 각 멤버들은 콤마(,)로 구분
  
• array : 대괄호([])로 시작하고 끝나며 각 값은 콤마(,)로 구분
  
• value : 값은 string, number, object, array, true, false, null 사용 가능
  
• string : 문자열은 쌍따옴표(")로 둘러 쌓여야 하며 Unicode character 또는 일반적인 escape 문자(\", \\, \/, \b, \f, \n, \r, \t, \u four-hex-digits)를 포함한다.
  
  
  
  

3.2 예시 #

{

"Image": {

  "Width":800,

  "Height":600,

  "Title":"View from 15th Floor",

  "Thumbnail":{

    "Url":"http:/\/scd.mm-b1.yimg.com\/image\/481989943",

    "Height": 125,

    "Width": "100"

  },

  "IDs":[ 116, 943, 234, 38793 ]

  }

} 

• 출처 : Yahoo JSON 예제
  
• 예제에서 Image는 최상위 object이고 모든 다른 데이터들은 이 object의 멤버.
  
• Width, Height, Title는 숫자와 문자열 데이타를 포함하고 있는 기본적인 멤버.
  
• Thumbnail은 Url, Height, Width를 멤버로 포함하고 있는 중첩 object.
  
• ?IDs는 숫자 값을 가지고 있는 array.
  
• Url 문자열 값에서 슬래쉬(/)가 escape 됨에 주의
  

4 참고 사이트 #

• JSON 공식
  
• JSON-PHP
  
• PHP-JSON
  
• PHP JSON Class
  
• YAHOO JSON

http://blog.naver.com/eclips32/30020578345

이 포스트를 보낸곳 ()

Simple Java toolkit for JSON (JSON.simple)
==========================================

http://www.JSON.org/java/json_simple.zip

1.Why the Simple Java toolkit (also named as JSON.simple) for JSON?

  When I use JSON as the data exchange format between the AJAX client and JSP
  for the first time, what worry me mostly is how to encode Java strings and
  numbers correctly in the server side so the AJAX client will receive a well
  formed JSON data. When I looked into the 'JSON in Java' directory in JSON
  website,I found that wrappers to JSONObject and JSONArray can be simpler,
  due to the simplicity of JSON itself. So I wrote the JSON.simple package.

2.Is it simple,really?

  I think so. Take an example:

  import org.json.simple.JSONObject;

  JSONObject obj=new JSONObject();
  obj.put("name","foo");
  obj.put("num",new Integer(100));
  obj.put("balance",new Double(1000.21));
  obj.put("is_vip",new Boolean(true));
  obj.put("nickname",null);
  System.out.print(obj);

  Result:
  {"nickname":null,"num":100,"balance":1000.21,"is_vip":true,"name":"foo"}

  The JSONObject.toString() will escape controls and specials correctly.

3.How to use JSON.simple in JSP?

  Take an example in JSP:

  <%@page contentType="text/html; charset=UTF-8"%>
  <%@page import="org.json.simple.JSONObject"%>
  <%
    JSONObject obj=new JSONObject();
    obj.put("name","foo");
    obj.put("num",new Integer(100));
    obj.put("balance",new Double(1000.21));
    obj.put("is_vip",new Boolean(true));
    obj.put("nickname",null);
    out.print(obj);
    out.flush();
  %>

  So the AJAX client will get the responseText.

4.Some details about JSONObject?

  JSONObject inherits java.util.HashMap,so it don't have to worry about the
  mapping things between keys and values. Feel free to use the Map methods
  like get(), put(), and remove() and others. JSONObject.toString() will
  combine key value pairs to get the JSON data string. Values will be escaped
  into JSON quote string format if it's an instance of java.lang.String. Other
  type of instance like java.lang.Number,java.lang.Boolean,null,JSONObject and
  JSONArray will NOT escape, just take their java.lang.String.valueOf() result.
  null value will be the JSON 'null' in the result.

  It's still correct if you put an instance of JSONObject or JSONArray into an
  instance of JSONObject or JSONArray. Take the example about:

  JSONObject obj2=new JSONObject();
  obj2.put("phone","123456");
  obj2.put("zip","7890");
  obj.put("contact",obj2);
  System.out.print(obj);

  Result:
  {"nickname":null,"num":100,"contact":{"phone":"123456","zip":"7890"},"balance":1000.21,"is_vip":true,"name":"foo"}

  The method JSONObject.escape() is used to escape Java string into JSON quote
  string. Controls and specials will be escaped correctly into \b,\f,\r,\n,\t,
  \",\\,\/,\uhhhh.

5.Some detail about JSONArray?

  org.json.simple.JSONArray inherits java.util.ArrayList. Feel free to use the
  List methods like get(),add(),remove(),iterator() and so on. The rules of
  JSONArray.toString() is similar to JSONObject.toString(). Here's the example:

  import org.json.simple.JSONArray;

  JSONArray array=new JSONArray();
  array.add("hello");
  array.add(new Integer(123));
  array.add(new Boolean(false));
  array.add(null);
  array.add(new Double(123.45));
  array.add(obj2);//see above
  System.out.print(array);

  Result:
  ["hello",123,false,null,123.45,{"phone":"123456","zip":"7890"}]

6.What is JSONValue for?

  org.json.simple.JSONValue is use to parse JSON data into Java Object.
  In JSON, the topmost entity is JSON value, not the JSON object. But
  it's not necessary to wrap JSON string,boolean,number and null again,
  for the Java has already had the according classes: java.lang.String,
  java.lang.Boolean,java.lang.Number and null. The mapping is:

  JSON          Java
  ------------------------------------------------
  string      <=>   java.lang.String
  number      <=>   java.lang.Number
  true|false  <=>   java.lang.Boolean
  null        <=>   null
  array       <=>   org.json.simple.JSONArray
  object      <=>       org.json.simple.JSONObject
  ------------------------------------------------

  JSONValue has only one kind of method, JSONValue.parse(), which receives
  a java.io.Reader or java.lang.String. Return type of JSONValue.parse()
  is according to the mapping above. If the input is incorrect in syntax or
  there's exceptions during the parsing, I choose to return null, ignoring
  the exception: I have no idea if it's a serious implementaion, but I think
  it's convenient to the user.

  Here's the example:

  String s="[0,{\"1\":{\"2\":{\"3\":{\"4\":[5,{\"6\":7}]}}}}]";
  Object obj=JSONValue.parse(s);
  JSONArray array=(JSONArray)obj;
  System.out.println(array.get(1));
  JSONObject obj2=(JSONObject)array.get(1);
  System.out.println(obj2.get("1"));

  Result:
  {"1":{"2":{"3":{"4":[5,{"6":7}]}}}}
  {"2":{"3":{"4":[5,{"6":7}]}}}

7.About the author.

  I'm a Java EE developer on Linux.
  I'm working on web systems and information retrieval systems.
  I also develop 3D games and Flash games.

  You can contact me through:
  Fang Yidong<fangyidong@yahoo.com.cn>
  Fang Yidong<fangyidng@gmail.com>

  http://www.JSON.org/java/json_simple.zip