PHP Json parsing

This article mainly introduces PHP Json analysis. Interested friends can refer to it. I hope it will be helpful to everyone.

Everyone should be familiar with JSON (JavaScript Object Notation). It is a lightweight data exchange format. Easy for humans to read and write. It is also 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 adopts a completely language-independent text format, but also uses conventions similar to the C language family (including C, C, C#, Java, JavaScript, Perl, Python, etc.). These features make JSON an ideal data exchange language.

JSON is constructed from two structures:

"Name/value"A collection of name/value pairs). In different languages, it is understood as object (object), record (record), structure (struct), dictionary (dictionary), hash table (hash table), with key list (keyed list), or associative array (associative array). An ordered list of values. In most languages, it is understood as an array (array).

PHP

#serialize is to serialize variables and return a variable type and structural string expressions. Speaking of which, both embody a data structure in the form of a string. So what is the difference between them?

Let’s start with

JSON

and look at a simple example.

Procedure1：

var test = {"Name":"Peter","Age":20};  
 
document.write(test.Name + ": " + test.Age);

Display results:

Peter: 20

##Variabletest中{"Name":"Peter","Age":20} is one with 2 An object of elements (feels like an array of PHP): Name is Peter, Age is 20.

Of course it can also become more complicated:

Program2：

var test = {"User":{"Name":"Peter","Age":20},"Company":"FORD"};  
 
document.write(test.User.Name + ": " + test.Company);

##Display results:

Peter: FORD

##In this example

User

# The ## element contains Name and Age.

If you want to reflect multiple

User

, you need to use an array, which is different from the object's "{}", use "[]" for arrays.

Procedure

3

：

var test = [  
           {"User":{"Name":"Peter","Age":20},"Company":"FORD"},  
           {"User":{"Name":"Li Ming","Age":20},"Company":"Benz"}  
       ];  
document.write(test[1].User.Name + ": " + test[1].Company);  
//或者使用：document.write(test[1]["User"]["Name"] + ": " + test[1]["Company"]);

Show results:

Li Ming: Benz

通过以上简单实例就能将一些复杂数据通过一个字符串来进行传递，再配合上Ajax的确是方便很多。

下面再来看看PHP的serialize函数的作用。

程序4：

$arr = array 
         (  
        'Peter'=> array 
       (  
        'Country'=>'USA',  
        'Age'=>20  
        ),  
          'Li Ming'=> array 
        (  
        'Country'=>'CHINA',  
        'Age'=>21  
       )  
       );  
$serialize_var = serialize($arr);  
echo $serialize_var;

显示结果：

a:2:{s:5:"Peter";a:2:{s:7:"Country";s:3:"USA";s:3:"Age";i:20;}s:7:"Li Ming";a:2:
{s:7:"Country";s:5:"CHINA";s:3:"Age";i:21;}}

这个结果看上去比JSON要复杂一些，其实也很简单，它说明的就是一些数据类型和结构。

以a:2:{s:7:"Country";s:3:"USA";s:3:"Age";i:20;}为例：

a:2说明这是个有两个元素的数组（array），s:7:"Country";s:3:"USA";为第一个元素，s:7说明这是有7个字符的字符串（string），后面i:20;也应该猜得到是整数（integer）20。

再来看一下这个例子：

程序5：

class test   
{  
  var $var = 0;  
   function add(){  
      echo $var+10;  
   }  
 }   
$unserialize_var = new test;  
$serialize_var = serialize($unserialize_var);  
echo $serialize_var;  
$unserialize_var = null;  
$unserialize_var = unserialize($serialize_var);  
$unserialize_var->add();

显示结果：

 O:4:"test":1:{s:3:"var";i:0;} 
 10

从这个例子中可以看出来，serialize对数据的类型和结构都进行的保存，unserialize后的变量仍然可以使用add（）方法。

那么PHP和JSON有没有联系呢，熟悉PHP的朋友应该了解PHP5.2.0已经将JSON extension设置为默认组件，也就是说我们可以在PHP中进行JSON操作，其函数为json_encode和json_decode。

程序6：

$arr = array 
       (  
         'Name'=>'Peter',  
          'Age'=>20  
      );      
$jsonencode = json_encode($arr);   
echo $jsonencode;

显示结果：

{"Name":"Peter","Age":20}

这个结果和例一中test值是一样的，通过json_encode将PHP中的变量转换为JSON字符出表达式。

再来看看json_decode的用法。

程序7：

$var = '{"Name":"Peter","Age":20}';  
 
$jsondecode = json_decode($var);  
 
print_r($jsondecode);

显示结果：

stdClass Object ( [Name] => Peter [Age] => 20 )

这的确验证了，在JSON中{"Name":"Peter","Age":20}是一个对象，但是在PHP中也可以将其转为数组，在json_decode中将ASSOC参数设置为True即可。

程序8：

$var = '{"Name":"Peter","Age":20}';  
 
$jsondecode = json_decode($var,true);  
 
print_r($jsondecode);

显示结果：

Array ( [Name] => Peter [Age] => 20 )

 

另，需要注意的是JSON是基于Unicode格式，所以要进行中文操作要将其转化为UTF-8格式。

 

通过上面这些例子相信大家对于JSON和PHP的serialize、json_encode都有了初步了解，结合PHP、Javascript、JSON以及Ajax就可以完成强大的数据交互功能。

 

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