Flex中JSON使用的一些总结

JSON(JavaScript Object Notation) 是一种轻量级的数 据交换格式,它采用完全独立于语言的文本格式,可 以用来在客户端和服务器端传输数据！JSON对象既可用于AJAX的开发中，也可用一般的J2EE的开发中，用于一次性向后台提交多于一条的记录！（譬如 显示在页面上的table中记录）
JSON官方网站的介绍：(www.json.org)

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.

JSON is built on two structures:


* A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.

* An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.



These are universal data structures. Virtually all modern programming languages support them in one form or another. It makes sense that a data format that is interchangable with programming languages also be based on these structures.

简单的示例：
1。var jsonObj={person1:{name:"jack",age:"12"},
person2:{name:"kate",age:"23"},
person3:{name:"jim",age:"14"}
};
调用JSON对象的属性,
1)jsonObj.person1.name
2)jsonObj["person1"].name
可以通过for循环的方式调用JSON对象中的每一个子对象
for(var p in jsonStr){
//alert(typeof p); alert(p);//返回的是string
str+=jsonObj[p].name+","+jsonObj[p].age+"<br>";
}

2。var jsonObj2={persons:[{name:"jordan",sex:"m",age:"40"},
{name:"bryant",sex:"m",age:"28"},
{name:"McGrady",sex:"m",age:"27"}
]};

调用JSON对象的属性,
1）jsonObj2.persons[0].name;
2）for循环调用方法，
var persons=jsonObj2.persons;//返回的值是一个数组object
for(var i=0;i<persons.length;i++){
cur_person=persons[i];
str+=cur_person.name+"'sex is "+cur_person.sex+" and age is "+cur_person.age+"<br>";
}
向jsonObj2的persons数组中插入,删除，更新 数据，
此处，可以利用javascript的Array对象的方法进行操作，如
var person={name:"yaoMing",sex:"m",age:"26"};
jsonObj2.persons.push(person);//数组最后加一条记录
jsonObj2.persons.pop();//删除最后一项
jsonObj2.persons.shift();//删除第一项
jsonObj2.persons.unshift(person);//数组最前面加一条记录
只要适合Javascript的方法都是可以用在JSON对象的数组中的！所以还有另外的方法splice( )进行crud操作！
//删除
jsonObj2.persons.splice(0,1);//开始位置,删除个数
//替换不删除
var self={name:"tom",sex:"m",age:"24"};
var brother={name:"Mike",sex:"m",age:"29"};
jsonObj2.persons.splice(1,0,self,brother);//开始位置,删除个数,插入对象
//替换并删除
var self={name:"tom",sex:"m",age:"24"};
var brother={name:"Mike",sex:"m",age:"29"};
jsonObj2.persons.splice(0,1,self,brother);//开始位置,删除个数,插入对象

二，知道了在Javascript中JSON的基本操作，但这还不能与后台进行交互，在着之前还需要把它转化为 String！

方法有两个，1）引入一个方法 ：

function obj2str(o){
var r = [];
if(typeof o =="string") return "\""+o.replace(/([\'\"\\])/g,"\\$1").replace(/(\n)/g,"\\n").replace(/(\r)/g,"\\r").replace(/(\t)/g,"\\t")+"\"";
if(typeof o == "object"){
if(!o.sort){
r[0]="{"
for(var i in o){
r[r.length]=i;
r[r.length]=":";
r[r.length]=obj2str(o[i]);
r[r.length]=",";
}
if(!!document.all && !/^\n?function\s*toString\(\)\s*\{\n?\s*\[native code\]\n?\s*\}\n?\s*$/.test(o.toString)){
r[r.length]="toString:"+o.toString.toString();
r[r.length]=",";
}
r[r.length-1]="}"
}else{
r[0]="["
for(var i =0;i<o.length;i++){
r[r.length]=obj2str(o[i]);
r[r.length]=",";
}
r[r.length-1]="]"
}
return r.join("");
}
return o.toString();
}

网上找的，还蛮好用地！！在此对原创者表示感谢啦！！