JSON中此错误的可能原因是什么？

Question

我正在一个Android应用程序中实现一个基本的注册系统，该系统通过wampserver和PHP API连接到SQL DATABASE ...每次执行注册过程时，用户都会保存在数据库中，但是当我尝试获取携带已注册用户信息并存储在与我的应用相关联的SQLite数据库中的过程...我得到以下错误提示：字符串无法转换为json对象。

这是Android端，在这里我调用PHP代码执行注册并接收json响应。

private void registerUser(final String name, final String email,
        final String password, final String latitude,
        final String longitude, final String userType) {
    // Tag used to cancel the request
    String tag_string_req = "req_register";

    pDialog.setMessage("Registering ...");
    showDialog();

    StringRequest strReq = new StringRequest(Method.POST,
            AppConfig.URL_REGISTER, new Response.Listener<String>() {

                @Override
                public void onResponse(String response) {
                    hideDialog();

                    try {
                        Log.i("tagconvertstr", "[" + response.toString()
                                + "]");


                        JSONObject jObj = new JSONObject(response);
                        boolean error = jObj.getBoolean("error");
                        if (!error) {
                            // User successfully stored in MySQL
                            // Now store the user in sqlite
                            String uid = jObj.getString("uid");

                            JSONObject user = jObj.getJSONObject("user");
                            String name = user.getString("name");
                            String email = user.getString("email");
                            String latitude = user.getString("latitude");
                            String longitude = user.getString("longitude");
                            String userType = user.getString("userType");
                            String service = user.getString("service");
                            String rate = user.getString("rate");
                            String rated_clients = user
                                    .getString("rated_clients");
                            String servicesTag = user
                                    .getString("servicesTag");
                            String created_at = user
                                    .getString("created_at");

                            // Inserting row in users table
                            db.addUser(name, email, latitude, longitude,
                                    userType, service, rate, rated_clients,
                                    servicesTag, uid, created_at);

                            Toast.makeText(
                                    getApplicationContext(),
                                    "User successfully registered. Try login now!",
                                    Toast.LENGTH_LONG).show();

                            // Launch login activity
                            checkLogin(email, password);

                        } else {
                            Log.d("heeeeeeeeeeeeeeeey", "error here");

                            // Error occurred in registration. Get the error
                            // message
                            String errorMsg = jObj.getString("error_msg");
                            toast.makeDialog("Error in registering "
                                    + errorMsg + "kk",
                                    getApplicationContext());
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    loginLayout.setVisibility(View.GONE);
                    registerLayout.setVisibility(View.GONE);
                    noConnectionLayout.setVisibility(View.VISIBLE);
                    tag = "register";
                    hideDialog();
                }
            }) {

        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("name", name);
            params.put("email", email);
            params.put("password", password);
            params.put("latitude", latitude);
            params.put("longitude", longitude);
            params.put("userType", userType);

            return params;
        }

    };
    strReq.setRetryPolicy(new DefaultRetryPolicy(0,
            DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
            DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}

我在以下行得到错误：JSONObject jObj = new JSONObject（response）;

这是注册过程的PHP代码：

<?php

ini_set ( 'display_errors', 'On' );

require_once 'include/DB_Functions.php';

$db = new DB_Functions ();

// json response array

$response = array (
"error" => FALSE 

`);

if (isset ( $_POST ['name'] ) && isset ( $_POST ['email'] ) && isset ( $_POST ['password'] ) && isset ( $_POST ['latitude'] ) && isset ( $_POST ['longitude'] ) && isset ( $_POST ['userType'] )) {



// receiving the post params
$name = $_POST ['name'];
$email = $_POST ['email'];
$password = $_POST ['password'];
$latitude = $_POST ['latitude'];
$longitude = $_POST ['longitude'];
$userType = $_POST ['userType'];

// check if user is already existed with the same email
if ($db->isUserExisted ( $email )) {
    // user already existed
    $response ["error"] = TRUE;
    $response ["error_msg"] = "User already existed with " . $email;
    echo json_encode ( $response );
} else {
    // create a new user
    $user = $db->storeUser ( $name, $email, $password, $latitude, $longitude, $userType );

    if ($user) {
        // user stored successfully
        $response ["error"] = FALSE;
        $response ["uid"] = $user ["unique_id"];
        $response ["user"] ["name"] = $user ["name"];
        $response ["user"] ["email"] = $user ["email"];
        $response ["user"] ["latitude"] = $user ["latitude"];
        $response ["user"] ["longitude"] = $user ["longitude"];
        $response ["user"] ["userType"] = $user ["userType"];
        $response ["user"] ["service"] = $user ["service"];
        $response ["user"] ["rate"] = $user ["rate"];
        $response ["user"] ["rated_clients"] = $user ["rated_clients"];
        $response ["user"] ["servicesTag"] = $user ["servicesTag"];
        $response ["user"] ["created_at"] = $user ["created_at"];
        $response ["user"] ["updated_at"] = $user ["updated_at"];
        echo json_encode ( $response );
    } else {

        // user failed to store
        $response ["error"] = TRUE;
        $response ["error_msg"] = "Unknown error occurred in registration!";
        echo json_encode ( $response );
    }
}
} else {
$response ["error"] = TRUE;
$response ["error_msg"] = "Required parameters (name, email or password) is missing!";
echo json_encode ( $response );
}
?>

这是isUserExicted和storeUser函数：

public function isUserExisted($email) {
    $stmt = $this->conn->prepare ( "SELECT email from users WHERE email = ?" );

    $stmt->bind_param ( "s", $email );

    $stmt->execute ();

    $stmt->store_result ();

    if ($stmt->num_rows > 0) {
        // user existed
        $stmt->close ();
        return true;
    } else {
        // user not existed
        $stmt->close ();
        return false;
    }
}


public function storeUser($name, $email, $password, $latitude, $longitude, $userType) {
    $uuid = uniqid ( '', true );
    $hash = $this->hashSSHA ( $password );
    $encrypted_password = $hash ["encrypted"]; // encrypted password
    $salt = $hash ["salt"]; // salt

    $service = "none";
    $rate = "none";
    $rated_clients = "none";
    $servicesTag = "none";

    $stmt = $this->conn->prepare ( "INSERT INTO users(unique_id, name, email, encrypted_password, latitude, longitude, userType, salt, service, rate, rated_clients, servicesTag, created_at) VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, NOW())" );
    $stmt->bind_param ( "ssssssssssss", $uuid, $name, $email, $encrypted_password, $latitude, $longitude, $userType, $salt, $service, $rate, $rated_clients, $servicesTag );
    $result = $stmt->execute ();
    $stmt->close ();
    var_dump ( $result );
    // check for successful store
    if ($result) {

        $stmt = $this->conn->prepare ( "SELECT * FROM users WHERE email = ?" );

        $stmt->bind_param ( "s", $email );

        $stmt->execute ();
        $user = $stmt->get_result ()->fetch_assoc ();
        $stmt->close ();
        var_dump ( $user );
        echo '</pre>';

        return $user;
    } else {

        return null;
    }
}

这是响应值：

注意：确保已在数据库中创建绑定到storeUser方法中查询的列。

Answer 1

您从服务器获取的json无效，您可以通过在以下站点上运行json来检查json的有效性：

http://www.jsoneditoronline.org/

该问题可能是由某些服务器错误引起的，或者您在生成的json之前回显了一些其他输出，这些输出是乞讨时的html标记。 我建议关闭错误，有关更多信息，请参见此处： 关闭显示错误PHP.ini

您可以使用.htaccess文件执行此操作，例如：

Options -Indexes

# suppress PHP errors from displaying in the browser
php_flag display_startup_errors off
php_flag display_errors off
php_flag html_errors off

# log PHP errors to a file
php_flag log_errors on
php_value error_reporting 32767
php_value error_log "./error_log.txt"

您的php通常应采用以下简化形式：

<?php
header('Content-type: application/json');
$json = file_get_contents('php://input'); // input json
// ...
$js_result = json_encode(array("error" => "unknown_action")); // result
echo $js_result;