Flutter向PHP API发送JSON数组数据的异常排查求助

问题根源 #

Flutter的http.post方法直接传入Map作为body时，默认会将数据编码为application/x-www-form-urlencoded格式，但你的PHP代码是通过file_get_contents("php://input")读取JSON格式的请求体，两者格式不匹配，导致PHP端拿到空数据。

解决方案 #

以下两种方式任选其一即可：

方式一：修改Flutter端，发送JSON格式数据 #

修改sendFormDataToApi方法，将Map转为JSON字符串并设置正确的请求头：

// 需在文件顶部导入dart:convert包
import 'dart:convert';

Future<void> sendFormDataToApi(Map<String, dynamic> formData) async {
  final apiUrl = 'http://kvb-bg.com/Sirena/test_api_adding_devices.php';

  try {
    final response = await http.post(
      Uri.parse(apiUrl),
      headers: {'Content-Type': 'application/json'}, // 指定JSON请求头
      body: jsonEncode(formData), // 将Map转为JSON字符串
    );

    if (response.statusCode == 200) {
      print('Response: ${response.body}'); // 打印响应内容用于调试
    } else {
      throw Exception('Failed to add device');
    }
  } catch (e) {
    throw Exception('Error: $e');
  }
}

方式二：修改PHP端，读取form-urlencoded格式数据 #

如果不想改动Flutter代码，直接让PHP读取POST表单数据：

<?php
$requestMethod = $_SERVER['REQUEST_METHOD'];

if ($requestMethod === 'POST') {
    // 直接通过$_POST读取表单字段
    $deviceName = isset($_POST['device_name1']) ? $_POST['device_name1'] : '';
    $deviceDescription = isset($_POST['device_description1']) ? $_POST['device_description1'] : '';
    $deviceCluster = isset($_POST['device_cluster1']) ? $_POST['device_cluster1'] : '';
    $deviceGeolocation1 = isset($_POST['device_geolocation11']) ? $_POST['device_geolocation11'] : '';
    $deviceGeolocation2 = isset($_POST['device_geolocation21']) ? $_POST['device_geolocation21'] : '';
    $sensorWater1Level = isset($_POST['sensor_water_1_level_1']) ? $_POST['sensor_water_1_level_1'] : '';
    $sensorWater2Level = isset($_POST['sensor_water_2_level_1']) ? $_POST['sensor_water_2_level_1'] : '';
    $sensorWater3Level = isset($_POST['sensor_water_3_level_1']) ? $_POST['sensor_water_3_level_1'] : '';
    $sensorLevel1AlertLevel = isset($_POST['sensor_level_1_alert_level_1']) ? $_POST['sensor_level_1_alert_level_1'] : '';
    $deviceWiFiName = isset($_POST['device_wifi_network_name1']) ? $_POST['device_wifi_network_name1'] : '';
    $deviceWiFiPassword = isset($_POST['device_wifi_network_password1']) ? $_POST['device_wifi_network_password1'] : '';
    $deviceMAC = isset($_POST['device_mac1']) ? $_POST['device_mac1'] : '';
} else {
    http_response_code(400);
    echo "Unsupported request method";
    exit();
}

// 数据库连接与操作
$servername = "localhost";
$username = "kvbbgcom_floodPrevention";
$password = "kv0889909595";
$dbname = "kvbbgcom_floodPrevention";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// 打印接收的数据用于调试
echo "Device Name: $deviceName\n";
echo " Device Description: $deviceDescription\n";
echo " Device Cluster: $deviceCluster\n";
echo " Device Geolocation 1: $deviceGeolocation1\n";
echo " Device Geolocation 2: $deviceGeolocation2\n";
echo " Sensor Water 1 Level: $sensorWater1Level\n";
echo " Sensor Water 2 Level: $sensorWater2Level\n";
echo " Sensor Water 3 Level: $sensorWater3Level\n";
echo " Sensor Level 1 Alert Level: $sensorLevel1AlertLevel\n";
echo " Device WiFi Name: $deviceWiFiName\n";
echo " Device WiFi Password: $deviceWiFiPassword\n";
echo " Device MAC: $deviceMAC\n";

// 启用数据库插入时，请使用预处理语句防止SQL注入
// $sql = "INSERT INTO devices (device_name, device_description, device_cluster, device_geolocation_1, device_geolocation_2, sensor_water_1_level, sensor_water_2_level, sensor_water_3_level, sensor_level_1_alert_level, device_wifi_network_name, device_wifi_network_password, device_mac)
// VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
// $stmt = $conn->prepare($sql);
// $stmt->bind_param("ssssssssssss", $deviceName, $deviceDescription, $deviceCluster, $deviceGeolocation1, $deviceGeolocation2, $sensorWater1Level, $sensorWater2Level, $sensorWater3Level, $sensorLevel1AlertLevel, $deviceWiFiName, $deviceWiFiPassword, $deviceMAC);
// if ($stmt->execute()) {
//     echo "New record created successfully";
// } else {
//     echo "Error: " . $stmt->error;
// }
// $stmt->close();

$conn->close();

exit();
?>

测试验证 #

• Flutter端点击提交后，查看控制台打印的Form Data确认数据收集正确
• PHP端可通过var_dump($_POST);（方式二）或var_dump($input);（方式一）验证数据是否接收成功

内容的提问来源于stack exchange，提问作者Konstantin Violinov