PHP：json_encode序列化中文字符和json_decode反序列化object

<?php
$name = '你好';
echo json_encode($name) . PHP_EOL;
// "\u4f60\u597d"
echo json_encode($name, JSON_UNESCAPED_UNICODE) . PHP_EOL;
// "你好"

<?php
$name = '{"name": "张翼德"}';
// echo json_decode($name) . PHP_EOL;
// PHP Fatal error:  Uncaught Error: Object of class stdClass could not be converted to string
var_dump(json_decode($name, true)) . PHP_EOL;
// array(1) {
//     ["name"]=> string(9) "张翼德"
// }