php json-schema -致命错误:未找到类

<?php
require_once 'vendor/autoload.php';

use JsonSchema\Validator;

// 定义 JSON Schema
$schema = '{
    "type": "object",
    "properties": {
        "name": {
            "type": "string"
        },
        "age": {
            "type": "integer",
            "minimum": 0
        }
    },
    "required": ["name"]
}';

// 要验证的 JSON 数据
$data = '{
    "name": "John",
    "age": 25
}';

// 解析 JSON Schema
$validator = new Validator();
$schemaObj = json_decode($schema);
$validator->validate(json_decode($data), $schemaObj);

// 验证结果
if ($validator->isValid()) {
    echo "JSON 数据验证通过\n";
} else {
    echo "JSON 数据验证失败\n";
    foreach ($validator->getErrors() as $error) {
        echo $error['property'] . ': ' . $error['message'] . "\n";
    }
}
?>