PHP结合React发起POST请求报trying to get property of non-object错

你遇到的trying to get property of non-object报错，核心是访问对象属性时目标变量不是合法对象，结合你的代码一共有3个触发问题：

• create.php中json_decode(file_get_contents("php://input"))解析失败（比如请求体为空、格式不是合法JSON）时会返回null，你没有做任何校验就直接取$data->name、$data->price，直接触发报错
• product.php里的INSERT SQL语句没有写字符串闭合，存在语法错误，就算参数传对了也会执行失败
• React端表单提交逻辑没有阻止默认刷新行为，会导致请求被中途中断，PHP端拿不到完整请求体

修复方案 #

1. 修复create.php的参数校验逻辑 #

增加JSON解析结果校验、必填参数校验，避免直接访问空值属性：

<?php 
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
header("Access-Control-Allow-Methods: POST");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");

include_once '../config/database.php';
include_once '../class/product.php';

$database = new Database();
$db = $database->getConnection();

$item = new Product($db);

$rawInput = file_get_contents("php://input");
$data = json_decode($rawInput);

// 校验解析结果和必填参数
if (json_last_error() !== JSON_ERROR_NONE || !$data || !isset($data->name) || !isset($data->price)) {
    http_response_code(400);
    echo json_encode(["message" => "参数错误，必须提交name和price字段"]);
    exit;
}

$item->name = $data->name;
$item->price = $data->price;

if ($item->createProduct()) {
    http_response_code(201);
    echo json_encode("Product created.");
} else {
    http_response_code(500);
    echo json_encode("Failed to create product.");
} 
?>

2. 修复product.php的SQL语法错误 #

补全SQL语句的字符串闭合，修正后的方法代码：

// POST request to create a product.
public function createProduct() {
    $sqlQuery = "INSERT INTO 
                ". $this->db_table ."
            SET
                name = :name,
                price = :price";

    $stmt = $this->conn->prepare($sqlQuery);
    
    // sanitize data
    $this->name=htmlspecialchars(strip_tags($this->name));
    $this->price=htmlspecialchars(strip_tags($this->price));

    // bind data
    $stmt->bindParam(":name", $this->name);
    $stmt->bindParam(":price", $this->price);

    if ($stmt->execute()) {
        return true;
    }

    return false;
}

3. 修复React端提交逻辑 #

阻止表单默认刷新行为，显式指定请求JSON格式，避免请求被中断、格式错误：

const onSubmit = (event) => {
    // 阻止表单默认提交刷新
    event.preventDefault();
    
    const product = {
        name: state.name,
        price: state.price,
    }

    console.log(product)

    axios.post('http://localhost:8080/api/create.php', product, {
        headers: {
            'Content-Type': 'application/json'
        }
    })
        .then(response => {
            if (response.data) {
                setProducts([...products, product])
            }
        })
        .catch(error => {
            console.log(error);
        })
}

验证要点 #

改完后按顺序检查：

• 浏览器控制台打印的product对象，name和price字段都有有效值，不是undefined
• 浏览器网络面板中POST请求的请求体是合法JSON，Content-Type为application/json
• 接口不再报non-object错误，数据能正常插入数据库

内容的提问来源于stack exchange，提问作者alizoubair