Json & Array from XML in 3 lines:

$xml = simplexml_load_string($xml_string);
$json = json_encode($xml);
$array = json_decode($json,TRUE);

Sorry for answering an old post, but this article outlines an approach that is relatively short, concise and easy to maintain. I tested it myself and works pretty well.

<?php   
class XmlToJson {
    public function Parse ($url) {
        $fileContents= file_get_contents($url);
        $fileContents = str_replace(array("\n", "\r", "\t"), '', $fileContents);
        $fileContents = trim(str_replace('"', "'", $fileContents));
        $simpleXml = simplexml_load_string($fileContents);
        $json = json_encode($simpleXml);

        return $json;
    }
}
?>

I guess I'm a bit late to the party but I have written a small function to accomplish this task. It also takes care of attributes, text content and even if multiple nodes with the same node-name are siblings.

Dislaimer: I'm not a PHP native, so please bear with simple mistakes.

function xml2js($xmlnode) {
    $root = (func_num_args() > 1 ? false : true);
    $jsnode = array();

    if (!$root) {
        if (count($xmlnode->attributes()) > 0){
            $jsnode["$"] = array();
            foreach($xmlnode->attributes() as $key => $value)
                $jsnode["$"][$key] = (string)$value;
        }

        $textcontent = trim((string)$xmlnode);
        if (count($textcontent) > 0)
            $jsnode["_"] = $textcontent;

        foreach ($xmlnode->children() as $childxmlnode) {
            $childname = $childxmlnode->getName();
            if (!array_key_exists($childname, $jsnode))
                $jsnode[$childname] = array();
            array_push($jsnode[$childname], xml2js($childxmlnode, true));
        }
        return $jsnode;
    } else {
        $nodename = $xmlnode->getName();
        $jsnode[$nodename] = array();
        array_push($jsnode[$nodename], xml2js($xmlnode, true));
        return json_encode($jsnode);
    }
}   

Usage example:

$xml = simplexml_load_file("myfile.xml");
echo xml2js($xml);

Example Input (myfile.xml):

<family name="Johnson">
    <child name="John" age="5">
        <toy status="old">Trooper</toy>
        <toy status="old">Ultrablock</toy>
        <toy status="new">Bike</toy>
    </child>
</family>

Example output:

{"family":[{"$":{"name":"Johnson"},"child":[{"$":{"name":"John","age":"5"},"toy":[{"$":{"status":"old"},"_":"Trooper"},{"$":{"status":"old"},"_":"Ultrablock"},{"$":{"status":"new"},"_":"Bike"}]}]}]}

Pretty printed:

{
    "family" : [{
            "$" : {
                "name" : "Johnson"
            },
            "child" : [{
                    "$" : {
                        "name" : "John",
                        "age" : "5"
                    },
                    "toy" : [{
                            "$" : {
                                "status" : "old"
                            },
                            "_" : "Trooper"
                        }, {
                            "$" : {
                                "status" : "old"
                            },
                            "_" : "Ultrablock"
                        }, {
                            "$" : {
                                "status" : "new"
                            },
                            "_" : "Bike"
                        }
                    ]
                }
            ]
        }
    ]
}

Quirks to keep in mind: Several tags with the same tagname can be siblings. Other solutions will most likely drop all but the last sibling. To avoid this each and every single node, even if it only has one child, is an array which hold an object for each instance of the tagname. (See multiple "" elements in example)

Even the root element, of which only one should exist in a valid XML document is stored as array with an object of the instance, just to have a consistent data structure.

To be able to distinguish between XML node content and XML attributes each objects attributes are stored in the "$" and the content in the "_" child.

Edit: I forgot to show the output for your example input data

{
    "states" : [{
            "state" : [{
                    "$" : {
                        "id" : "AL"
                    },
                    "name" : [{
                            "_" : "Alabama"
                        }
                    ]
                }, {
                    "$" : {
                        "id" : "AK"
                    },
                    "name" : [{
                            "_" : "Alaska"
                        }
                    ]
                }
            ]
        }
    ]
}

A common pitfall is to forget that json_encode() does not respect elements with a textvalue and attribute(s). It will choose one of those, meaning dataloss. The function below solves that problem. If one decides to go for the json_encode/decode way, the following function is advised.

function json_prepare_xml($domNode) {
  foreach($domNode->childNodes as $node) {
    if($node->hasChildNodes()) {
      json_prepare_xml($node);
    } else {
      if($domNode->hasAttributes() && strlen($domNode->nodeValue)){
         $domNode->setAttribute("nodeValue", $node->textContent);
         $node->nodeValue = "";
      }
    }
  }
}

$dom = new DOMDocument();
$dom->loadXML( file_get_contents($xmlfile) );
json_prepare_xml($dom);
$sxml = simplexml_load_string( $dom->saveXML() );
$json = json_decode( json_encode( $sxml ) );

by doing so, <foo bar="3">Lorem</foo> will not end up as {"foo":"Lorem"} in your JSON.

Try to use this

$xml = ... // Xml file data

// first approach
$Json = json_encode(simplexml_load_string($xml));

---------------- OR -----------------------

// second approach
$Json = json_encode(simplexml_load_string($xml, "SimpleXMLElement", LIBXML_NOCDATA));

echo $Json;

Or

You can use this library :

This solution handles namespaces, attributes, and produces consistent result with repeating elements (always in array, even if there is only one occurrence). Inspired by ratfactor's sxiToArray().

/**
 * <root><a>5</a><b>6</b><b>8</b></root> -> {"root":[{"a":["5"],"b":["6","8"]}]}
 * <root a="5"><b>6</b><b>8</b></root> -> {"root":[{"a":"5","b":["6","8"]}]}
 * <root xmlns:wsp=""><a>123</a><wsp:b>456</wsp:b></root> 
 *   -> {"root":[{"xmlns:wsp":"","a":["123"],"wsp:b":["456"]}]}
 */
function domNodesToArray(array $tags, \DOMXPath $xpath)
{
    $tagNameToArr = [];
    foreach ($tags as $tag) {
        $tagData = [];
        $attrs = $tag->attributes ? iterator_to_array($tag->attributes) : [];
        $subTags = $tag->childNodes ? iterator_to_array($tag->childNodes) : [];
        foreach ($xpath->query('namespace::*', $tag) as $nsNode) {
            // the only way to get xmlns:*, see 
            if ($tag->hasAttribute($nsNode->nodeName)) {
                $attrs[] = $nsNode;
            }
        }

        foreach ($attrs as $attr) {
            $tagData[$attr->nodeName] = $attr->nodeValue;
        }
        if (count($subTags) === 1 && $subTags[0] instanceof \DOMText) {
            $text = $subTags[0]->nodeValue;
        } elseif (count($subTags) === 0) {
            $text = '';
        } else {
            // ignore whitespace (and any other text if any) between nodes
            $isNotDomText = function($node){return !($node instanceof \DOMText);};
            $realNodes = array_filter($subTags, $isNotDomText);
            $subTagNameToArr = domNodesToArray($realNodes, $xpath);
            $tagData = array_merge($tagData, $subTagNameToArr);
            $text = null;
        }
        if (!is_null($text)) {
            if ($attrs) {
                if ($text) {
                    $tagData['_'] = $text;
                }
            } else {
                $tagData = $text;
            }
        }
        $keyName = $tag->nodeName;
        $tagNameToArr[$keyName][] = $tagData;
    }
    return $tagNameToArr;
}

function xmlToArr(string $xml)
{
    $doc = new \DOMDocument();
    $doc->loadXML($xml);
    $xpath = new \DOMXPath($doc);
    $tags = $doc->childNodes ? iterator_to_array($doc->childNodes) : [];
    return domNodesToArray($tags, $xpath);
}

Example:

php > print(json_encode(xmlToArr('<root a="5"><b>6</b></root>')));
{"root":[{"a":"5","b":["6"]}]}

I've used Miles Johnson's TypeConverter for this purpose. It's installable using Composer.

You could write something like this using it:

<?php
require 'vendor/autoload.php';
use mjohnson\utility\TypeConverter;

$xml = file_get_contents("file.xml");
$arr = TypeConverter::xmlToArray($xml, TypeConverter::XML_GROUP);
echo json_encode($arr);

Optimizing Antonio Max answer:

$xmlfile = 'yourfile.xml';
$xmlparser = xml_parser_create();

// open a file and read data
$fp = fopen($xmlfile, 'r');
//9999999 is the length which fread stops to read.
$xmldata = fread($fp, 9999999);

// converting to XML
$xml = simplexml_load_string($xmldata, "SimpleXMLElement", LIBXML_NOCDATA);

// converting to JSON
$json = json_encode($xml);
$array = json_decode($json,TRUE);

Best solution which works like a charm

$fileContents= file_get_contents($url);

$fileContents = str_replace(array("\n", "\r", "\t"), '', $fileContents);

$fileContents = trim(str_replace('"', "'", $fileContents));

$simpleXml = simplexml_load_string($fileContents);

//$json = json_encode($simpleXml); // Remove // if you want to store the result in $json variable

echo '<pre>'.json_encode($simpleXml,JSON_PRETTY_PRINT).'</pre>';

Source

if you XML is a soap file, you can use this:

$xmlStr = preg_replace("/(<\/?)(\w+):([^>]*>)/", "$1$2$3", $xmlStr);
$xml = new SimpleXMLElement($xmlStr);
return json_encode($xml);

        $content = str_replace(array("\n", "\r", "\t"), '', $response);
        $content = trim(str_replace('"', "'", $content));
        $xml = simplexml_load_string($content);
        $json = json_encode($xml);
        return json_decode($json,TRUE);

This worked for me

If you would like to only convert a specific part of the XML to JSON, you can use XPath to retrieve this and convert that to JSON.

<?php
$file = @file_get_contents($xml_File, FILE_TEXT);
$xml = new SimpleXMLElement($file);
$xml_Excerpt = @$xml->xpath('/states/state[@id="AL"]')[0]; // [0] gets the node
echo json_encode($xml_Excerpt);
?>

Please note that if you Xpath is incorrect, this will die with an error. So if you're debugging this through AJAX calls I recommend you log the response bodies as well.

This is an improvement of the most upvoted solution by Antonio Max, which also works with XML that has namespaces (by replacing the colon with an underscore). It also has some extra options (and does parse <person my-attribute='name'>John</person> correctly).

function parse_xml_into_array($xml_string, $options = array()) {
    /*
    DESCRIPTION:
    - parse an XML string into an array
    INPUT:
    - $xml_string
    - $options : associative array with any of these keys:
        - 'flatten_cdata' : set to true to flatten CDATA elements
        - 'use_objects' : set to true to parse into objects instead of associative arrays
        - 'convert_booleans' : set to true to cast string values 'true' and 'false' into booleans
    OUTPUT:
    - associative array
    */

    // Remove namespaces by replacing ":" with "_"
    if (preg_match_all("|</([\\w\\-]+):([\\w\\-]+)>|", $xml_string, $matches, PREG_SET_ORDER)) {
        foreach ($matches as $match) {
            $xml_string = str_replace('<'. $match[1] .':'. $match[2], '<'. $match[1] .'_'. $match[2], $xml_string);
            $xml_string = str_replace('</'. $match[1] .':'. $match[2], '</'. $match[1] .'_'. $match[2], $xml_string);
        }
    }

    $output = json_decode(json_encode(@simplexml_load_string($xml_string, 'SimpleXMLElement', ($options['flatten_cdata'] ? LIBXML_NOCDATA : 0))), ($options['use_objects'] ? false : true));

    // Cast string values "true" and "false" to booleans
    if ($options['convert_booleans']) {
        $bool = function(&$item, $key) {
            if (in_array($item, array('true', 'TRUE', 'True'), true)) {
                $item = true;
            } elseif (in_array($item, array('false', 'FALSE', 'False'), true)) {
                $item = false;
            }
        };
        array_walk_recursive($output, $bool);
    }

    return $output;
}

This is better solution

$fileContents= file_get_contents("");
$fileContents = str_replace(array("\n", "\r", "\t"), '', $fileContents);
$fileContents = trim(str_replace('"', "'", $fileContents));
$simpleXml = simplexml_load_string($fileContents);
$json = json_encode($simpleXml);
$array = json_decode($json,TRUE);
return $array;

Found FTav's answer the most useful as it is very customizable, but his xml2js function has some flaws. For instance, if children elements has equal tagnames they all will be stored in a single object, this means that the order of elements will not be preserved. In some cases we really want to preserve order, so we better store every element's data in a separate object:

function xml2js($xmlnode) {
    $jsnode = array();
    $nodename = $xmlnode->getName();
    $current_object = array();

    if (count($xmlnode->attributes()) > 0) {
        foreach($xmlnode->attributes() as $key => $value) {
            $current_object[$key] = (string)$value;
        }
    }

    $textcontent = trim((string)$xmlnode);
    if (strlen($textcontent) > 0) {
        $current_object["content"] = $textcontent;
    }

    if (count($xmlnode->children()) > 0) {
        $current_object['children'] = array();
        foreach ($xmlnode->children() as $childxmlnode) {
            $childname = $childxmlnode->getName();
            array_push($current_object['children'], xml2js($childxmlnode, true));
        }
    }

    $jsnode[ $nodename ] = $current_object;
    return $jsnode;
}

Here is how it works. Initial xml structure:

<some-tag some-attribute="value of some attribute">
  <another-tag>With text</another-tag>
  <surprise></surprise>
  <another-tag>The last one</another-tag>
</some-tag>

Result JSON:

{
    "some-tag": {
        "some-attribute": "value of some attribute",
        "children": [
            {
                "another-tag": {
                    "content": "With text"
                }
            },
            {
                "surprise": []
            },
            {
                "another-tag": {
                    "content": "The last one"
                }
            }
        ]
    }
}

All solutions here have problems!

... When the representation need perfect XML interpretation (without problems with attributes) and to reproduce all text-tag-text-tag-text-... and order of tags. Also good remember here that JSON object "is an unordered set" (not repeat keys and the keys can't have predefined order)... Even ZF's xml2json is wrong (!) because not preserve exactly the XML structure.

All solutions here have problems with this simple XML,

    <states x-x='1'>
        <state y="123">Alabama</state>
        My name is <b>John</b> Doe
        <state>Alaska</state>
    </states>

... @FTav solution seems better than 3-line solution, but also have little bug when tested with this XML.