Introducing JSON and XML format conversion in PHP

During the development process, data format conversion is a common problem. In PHP, the two commonly used data formats are JSON and XML. JSON is a lightweight data exchange format that is easy to read and write, while XML is an extensible markup language that is widely used in Web data transmission and configuration file storage.

This article will introduce how to convert JSON format to XML format in PHP.

1. JSON to XML

PHP provides the function json_decode() that can be used to convert JSON data into XML format. The syntax is as follows:

mixed json_decode ( string $json [, bool $assoc = false [, int $depth = 512 [, int $options = 0 ]]] )

Among them, $json represents the JSON string to be converted, $assoc represents whether to convert the JSON object into an associative array (default is false), $depth represents the maximum recursion depth (default is 512 ), $options represents conversion options (default is 0).

The following is an example of converting a JSON array into XML:

<?php // JSON数据
$json_data = &#39;{
    "students": [
        {
            "name": "David",
            "age": 20,
            "score": {
                "English": 90,
                "Math": 85,
                "Chinese": 95
            }
        },
        {
            "name": "Tom",
            "age": 22,
            "score": {
                "English": 80,
                "Math": 75,
                "Chinese": 85
            }
        }
    ]
}&#39;;

// 将JSON数据转换成PHP数组
$php_data = json_decode($json_data, true);

// 将PHP数组转换成XML格式
$xml_data = new SimpleXMLElement(&#39;<?xml version="1.0" encoding="UTF-8"?><data></data>');
array_to_xml($php_data, $xml_data);

// 输出XML格式数据
header('Content-type: text/xml');
echo $xml_data->asXML();

// 将数组转换成XML格式的函数
function array_to_xml($arr, &$xml) {
    foreach ($arr as $key => $value) {
        if (is_array($value)) {
            if (!is_numeric($key)) {
                $subnode = $xml->addChild("$key");
                array_to_xml($value, $subnode);
            } else {
                array_to_xml($value, $xml);
            }
        } else {
            $xml->addChild("$key", htmlspecialchars("$value"));
        }
    }
}
?>

The above code first converts the JSON string into a PHP array, and then uses a recursive function to convert the PHP array into XML format.

The output XML format data is as follows:

<?xml  version="1.0" encoding="UTF-8"?>
<data>
  <students>
    
      <name>David</name>
      <age>20</age>
      <score>
        <english>90</english>
        <math>85</math>
        <chinese>95</chinese>
      </score>
    0>
    
      <name>Tom</name>
      <age>22</age>
      <score>
        <english>80</english>
        <math>75</math>
        <chinese>85</chinese>
      </score>
    1>
  </students>
</data>

2. XML to JSON

To convert XML format to JSON format, you need to convert XML to PHP array first, and then Use the json_encode() function to convert a PHP array into a JSON string. The following is an example of converting XML to JSON:

<?php // XML数据
$xml_data = &#39;<?xml version="1.0" encoding="UTF-8"?>
<data>
  <students>
    
      <name>David</name>
      <age>20</age>
      <score>
        <english>90</english>
        <math>85</math>
        <chinese>95</chinese>
      </score>
    0>
    
      <name>Tom</name>
      <age>22</age>
      <score>
        <english>80</english>
        <math>75</math>
        <chinese>85</chinese>
      </score>
    1>
  </students>
</data>';

// 将XML数据转换成PHP数组
$php_data = xml_to_array(simplexml_load_string($xml_data));

// 将PHP数组转换成JSON字符串
$json_data = json_encode($php_data);

// 输出JSON格式数据
header('Content-type: text/json');
echo $json_data;

// 将XML数据转换成PHP数组的函数
function xml_to_array($xml) {
    $arr = array();
    foreach ($xml->children() as $element) {
        if (count($element->children()) == 0) {
            $arr[$element->getName()] = strval($element);
        } else {
            $arr[$element->getName()][] = xml_to_array($element);
        }
    }
    return $arr;
}
?>

The above code first converts the XML string into a SimpleXMLElement object through the simplexml_load_string() function, and then converts the SimpleXMLElement object into a PHP array through the recursive function. Finally, use the json_encode() function to convert the PHP array into a JSON string.

The output JSON format data is as follows:

{
  "students": [
    {
      "name": "David",
      "age": "20",
      "score": {
        "English": "90",
        "Math": "85",
        "Chinese": "95"
      }
    },
    {
      "name": "Tom",
      "age": "22",
      "score": {
        "English": "80",
        "Math": "75",
        "Chinese": "85"
      }
    }
  ]
}

Summary

PHP provides convenient functions for converting JSON format to XML format and XML format to JSON format. During the development process, choosing the appropriate data format for storage and exchange based on actual needs can achieve better data transmission and reading effects.

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