<?php
$data = [
    'name' => '张三',
    'age' => 30,
    'isStudent' => false,
    'hobbies' => ['reading', 'coding', 'travel'],
    'address' => [
        'city' => '北京',
        'zip' => '100000'
    ]
];

$jsonString = json_encode($data);
echo $jsonString;
// 输出: {"name":"/u5f20/u4e09","age":30,"isStudent":false,"hobbies":["reading","coding","travel"],"address":{"city":"/u5317/u4eac","zip":"100000"}}
?>

/uXXXX

JSON_UNESCAPED_UNICODE

<?php
$jsonStringPretty = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
echo $jsonStringPretty;
/*
输出:
{
    "name": "张三",
    "age": 30,
    "isStudent": false,
    "hobbies": [
        "reading",
        "coding",
        "travel"
    ],
    "address": {
        "city": "北京",
        "zip": "100000"
    }
}
*/
?>

JSON_PRETTY_PRINT

true

false

<?php
$jsonStringReceived = '{"name":"李四","age":25,"city":"上海"}';

// 解码为对象
$obj = json_decode($jsonStringReceived);
echo $obj->name; // 输出: 李四

// 解码为关联数组
$arr = json_decode($jsonStringReceived, true);
echo $arr['name']; // 输出: 李四

// 如果 JSON 字符串是数组形式
$jsonArrayString = '[{"id":1,"name":"A"},{"id":2,"name":"B"}]';
$arrayResult = json_decode($jsonArrayString, true);
print_r($arrayResult);
/*
输出:
Array
(
    [0] => Array
        (
            [id] => 1
            [name] => A
        )

    [1] => Array
        (
            [id] => 2
            [name] => B
        )

)
*/
?>

private

protected

json_last_error()

json_last_error_msg()

<?php
$invalidJson = '{"name": "张三", "age": 30, }'; // 多余的逗号

$data = json_decode($invalidJson);

if ($data === null && json_last_error() !== JSON_ERROR_NONE) {
    echo "JSON 解码失败: " . json_last_error_msg();
    // 可能会输出: JSON 解码失败: Syntax error
}

$anotherInvalidJson = '{"id":1,"name":"测试"'; // 缺少右大括号
$data2 = json_decode($anotherInvalidJson);
if ($data2 === null && json_last_error() !== JSON_ERROR_NONE) {
    echo "/nJSON 解码失败: " . json_last_error_msg();
    // 可能会输出: JSON 解码失败: Syntax error
}
?>

JSON_BIGINT_AS_STRING

<?php
$jsonWithBigInt = '{"id": 9223372036854775807, "value": 12345678901234567890}'; // 922... 是 64 位 PHP int 的最大值

// 默认解码
$objDefault = json_decode($jsonWithBigInt);
var_dump($objDefault->value); // 可能会是 float(1.2345678901235E+19) 或其他不精确的值

// 使用 JSON_BIGINT_AS_STRING
$objString = json_decode($jsonWithBigInt, false, 512, JSON_BIGINT_AS_STRING);
var_dump($objString->value); // 字符串 "12345678901234567890"
?>

jsonSerialize()

<?php
class Product implements JsonSerializable {
    private $id;
    public $name;
    protected $price;
    public $description;
    public $createdAt; // DateTime object

    public function __construct($id, $name, $price, $description) {
        $this->id = $id;
        $this->name = $name;
        $this->price = $price;
        $this->description = $description;
        $this->createdAt = new DateTime();
    }

    // 实现 JsonSerializable 接口
    public function jsonSerialize(): mixed {
        // 只暴露 id, name, price (四舍五入到两位小数), description
        // 并将 createdAt 格式化为字符串
        return [
            'product_id' => $this->id,
            'product_name' => $this->name,
            'price_usd' => round($this->price, 2),
            'short_desc' => substr($this->description, 0, 50) . '...',
            'created_at_iso' => $this->createdAt->format(DateTime::ISO8601),
            // 假设我们不想暴露原始的 description 或者 private/protected 属性
        ];
    }
}

$product = new Product(101, '超薄笔记本电脑', 1299.998, '这是一款性能卓越、设计轻薄的笔记本电脑，非常适合商务人士和学生使用。');
$jsonProduct = json_encode($product, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
echo $jsonProduct;
/*
输出:
{
    "product_id": 101,
    "product_name": "超薄笔记本电脑",
    "price_usd": 1300,
    "short_desc": "这是一款性能卓越、设计轻薄的笔记本电脑，...",
    "created_at_iso": "2023-10-27T10:00:00+0800" // 时间会根据实际生成
}
*/
?>

<?php
$dataWithEmptyArray = ['items' => []];
echo json_encode($dataWithEmptyArray); // {"items":[]}
echo "/n";
echo json_encode($dataWithEmptyArray, JSON_FORCE_OBJECT); // {"items":{}}
?>

<?php
$profile = [
    'name' => '王五',
    'email' => 'wangwu@example.com',
    'phone' => null, // 空值
    'address' => '', // 空字符串
    'tags' => [] // 空数组
];

// 过滤掉 null 和空字符串的辅助函数
$filteredProfile = array_filter($profile, function($value) {
    return $value !== null && $value !== '';
});

// 如果也想过滤空数组，可以进一步处理
$filteredProfile = array_filter($filteredProfile, function($value) {
    return !is_array($value) || !empty($value);
});

echo json_encode($filteredProfile, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
/*
输出:
{
    "name": "王五",
    "email": "wangwu@example.com"
}
*/
?>

justinrainbow/json-schema

<?php
$apiResponse = '{"user_id": 123, "username": "test_user", "is_active": "true"}'; // 注意 is_active 是字符串

$data = json_decode($apiResponse, true);

// 检查是否解码成功且不是 null
if ($data === null) {
    echo "JSON 解码失败或为空。/n";
    // 检查 json_last_error()
    exit;
}

// 验证关键字段是否存在
if (!isset($data['user_id']) || !isset($data['username'])) {
    echo "缺少必要字段。/n";
    exit;
}

// 验证字段类型
if (!is_int($data['user_id'])) {
    // 尝试转换为整数，或报错
    $data['user_id'] = (int)$data['user_id'];
    echo "user_id 类型不正确，已尝试转换。/n";
}

// 验证布尔值
if (isset($data['is