_php instances using JSON in the PHP language and restoring JSON to an array of methods

Before I wrote a simple example of PHP return JSON data, just online, suddenly found an article, also introduced JSON, very detailed, worth reference. The contents are as follows

Starting with version 5.2, PHP native provides the Json_encode () and Json_decode () functions, which are used for encoding, which is used for decoding.

First, Json_encode ()

Output

Let's look at an example of an object conversion:

$obj->body      = ' another post '; $obj->id       =; $obj->approved    = true; $obj->favorite_count = 1; $ Obj->status     

Output

Because JSON accepts only utf-8 encoded characters, the Json_encode () argument must be utf-8 encoded, otherwise it will get a null character or null. This is especially important when using GB2312 encoding in Chinese, or when using ISO-8859-1 encoding in a foreign language.

Second, indexed arrays and associative arrays

PHP supports two arrays, one is an indexed array (indexed array) that only holds "value", and the other is an associative array (associative array) that holds "name value pairs" (name/value).

Because JavaScript does not support associative arrays, json_encode () only converts an indexed array (indexed array) into an array format, and the associative array (associative array) to the object format.

For example, there is now an indexed array

Output

If you change it to an associative array:

$arr = Array (' 1 ' = ' one ', ' 2 ' = '-'-', ' 3 ' = ' three ');  echo Json_encode ($arr);

Output becomes

Note that the data format has changed from "[]" (array) to "{}" (object).

If you need to force an "indexed array" into an "object", you can write

Or

Iii. Conversion of classes (class)

The following is a PHP class:

Class Foo {const   error_code = ' 404 '; 　　 　　　　Public  $public _EX = ' the public '; 　　 　　　　Private  $private _ex = ' this is private! '; protected $protected _EX = ' This should is protected ';  

Now, JSON transforms the instance of this class:

The output is

As you can see, other things (constants, private variables, methods, and so on) are lost in addition to the public variables.

Iv. Json_decode ()

This function is used to convert the JSON text to the appropriate PHP data structure. Here is an example:

$json = ' {' foo ': 12345} ';  

Typically, Json_decode () always returns a PHP object instead of an array. Like what:

$json = ' {' A ': 1, ' B ': 2, ' C ': 3, ' d ': 4, ' E ': 5} ';  

The result is to generate a PHP object:

If you want to force a PHP associative array to be generated, json_decode () needs to add a parameter of true:

$json = ' {' A ': 1, ' B ': 2, ' C ': 3, ' d ': 4, ' E ': 5} ';  

As a result, an associative array is generated:

V. Common errors in Json_decode ()

The following three kinds of JSON notation are wrong, can you see where is wrong?

Executing Json_decode () on these three strings will return null and error.

The first error is that the JSON delimiter (delimiter) only allows double quotation marks and cannot use single quotes. The second error is the "name" of the JSON name-value pair (the left part of the colon), which must use double quotes in any case. The third error is that you cannot add a comma after the last value (trailing comma).

In addition, JSON can only be used to represent objects (object) and Arrays (array), and if you use Json_decode () for a string or numeric value, NULL will be returned.

This article in the PHP language using JSON and the JSON to restore the array of methods is small part of the whole content to share to everyone, I hope to give you a reference, but also hope that we support the script home.

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