volley.parserror:org.json.JSONException:java.lang.string类型的值br无法转换为JSONObject

volley.parserror:org.json

无法将java.lang.string类型的值br转换为JSONObject

安卓代码

public void performSearch() {
            String url= "http://192.168.0.136/fyp/stitle.php";
            RequestQueue requestQueue = Volley.newRequestQueue(Stitle.this);
           JsonObjectRequest jsObjRequest = new JsonObjectRequest(Request.Method.POST,url,null,
                   new Response.Listener<JSONObject>() {
               @Override
               public void onResponse(JSONObject response) {
                   Log.i("Response", response.toString());
                   try {
                       //converting the string to json array object
                       JSONObject array = new JSONObject();
                       Log.i("test", " value : " + array.getString("status"));
                       if (array.getString("status").equals("true")) {
                           JSONArray jsonArray = array.getJSONArray("search");
                           Log.i("test", " value : " + array);

                           for (int i = 0; i < jsonArray.length(); i++) {

                               //getting product object from json array
                               JSONObject product = jsonArray.getJSONObject(i);

                               //adding the product to product list
                               boolean add = productList.add(new list(
                                       product.getLong("isbn"),
                                       product.getString("title"),
                                       product.getString("authors"),
                                       product.getInt("accession"),
                                       product.getString("publisher"),
                                       product.getInt("pubyear"),
                                       product.getInt("pages"),
                                       product.getInt("rak"),
                                       product.getInt("hr"),
                                       product.getInt("vr"),
                                       product.getLong("barcode")

                               ));

                           }

                       } else {
                           Log.i("test", "else error");

                       }


                   } catch (JSONException e) {
                       e.printStackTrace();
                       Log.i("test", e.toString());
                   }
               }

           }, new Response.ErrorListener() {
               @Override
               public void onErrorResponse(VolleyError error) {
                   Toast.makeText(getApplicationContext(), "error:" + error.toString(), Toast.LENGTH_LONG).show();

               }
           }) {
               @Override
               protected Map<String, String> getParams() throws AuthFailureError {

                   Map<String, String> params = new HashMap<>();
                   params.put("Title", searchtitle.getText().toString());

                   return params;
               }
           };
           requestQueue = Volley.newRequestQueue(Stitle.this);
           requestQueue.add(jsObjRequest);

        }

        }

public void performSearch（）{
字符串url=”http://192.168.0.136/fyp/stitle.php";
RequestQueue RequestQueue=Volley.newRequestQueue（Stitle.this）；
JsonObjectRequest jsObjRequest=新的JsonObjectRequest（Request.Method.POST，url，null，
新的Response.Listener（）{
@凌驾
公共void onResponse（JSONObject响应）{
Log.i（“Response”，Response.toString（））；
试一试{
//将字符串转换为json数组对象
JSONObject数组=新的JSONObject（）；
Log.i（“测试”，“值：”+array.getString（“状态”））；
if（array.getString（“status”）.equals（“true”））{
JSONArray JSONArray=array.getJSONArray（“搜索”）；
Log.i（“测试”，“值：”+数组）；
for（int i=0；i

将json发送到android java文件的Php代码文件

---

您的代码有几个问题。首先，让我们来处理您的PHP。您的PHP代码应该设计为返回一些有用的信息，无论它是成功的还是失败的——以及失败的原因

我不知道您使用哪个类访问MySQL数据，但无论如何它都不是
PDO
。我将向您展示一个使用
PDO
的示例，因为您可以使用准备好的语句，这将有助于保护您免受SQL注入攻击。
您的PHP代码设计糟糕，此外，它还容易受到SQL注入攻击

在PHP代码开始时，先对参数进行
isset
检查。无论查询是否失败，此代码都将返回一个
JSONObject
。这使得我们更容易发现什么地方出了问题——什么时候出了问题

<?php

// array for JSON response
$response = array();
//set values just in case any thing goes wrong
$response["status"] = 0;
$response["message"] = "Error before start";

// check for post data with isset
if (isset($_POST["Title"])) {

    $title = $_POST["Title"];

    // You were not using PDO so I dumped your connection and require you to provide...
    //...a configuration file for ...
    require_once __DIR__ . '/db_config.php';
    // ...these  variables
    $host = DB_SERVER;
    $db   = DB_DATABASE;
    $user = DB_USER;
    $pass = DB_PASSWORD;
    $charset = 'utf8';

    $dsn = "mysql:host=$host;dbname=$db;charset=$charset";
    $opt = [
        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES   => false,
    ];

    try{
        // connecting to db with PDO
        $pdo = new PDO($dsn, $user, $pass, $opt);


        $sql = 'SELECT isbn, title, authors, accession, publisher, pubyear, pages, rak, hr, vr, barcode
                FROM books 
                WHERE title LIKE :titleParam';

        $titleParam = "%".$title."%";

        $stmt = $pdo->prepare($sql);

        // Bind the parameter
        $stmt->bindParam(':titleParam', $titleParam, PDO::PARAM_STR);

        $res = $stmt->execute();

        if ($res) {
            // success
            $response["status"] = 1;
            // connection node
            $response["books"] = array();

            while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
                $data = array();
                $data["isbn"] = $row["isbn"];
                $data["title"] = $row["title"];
                $data["authors"] = $row["authors"];
                $data["accession"] = $row["accession"];
                $data["publisher"] = $row["publisher"];
                $data["pubyear"] = $row["pubyear"];
                $data["pages"] = $row["pages"];
                $data["rak"] = $row["rak"];
                $data["hr"] = $row["hr"];
                $data["vr"] = $row["vr"];
                $data["barcode"] = $row["barcode"];

                array_push($response["books"], $data);
            }
        }
        else {
            // required field is missing
            $response["status"] = 2;
            $response["message"] = "No data returned";
        }   
    }
    catch (Exception $e){
        $response["status"] = 3;
        $response["message"] = "Error occurred." . $e->getMessage();
    }
}
else {
    $response["status"] = 4;
    $response["message"] = "Post parameters are not correct";
}
// echoing JSON response
echo json_encode($response);
?>


将结果记录到logcat中，以便查看返回的JSON响应，然后发布数据示例。您应该被告知PHP代码已打开，可以进行SQL注入！您还应该使用
isset
检查POST参数，因此如果参数设置不正确，PHP代码将优雅地退出。logcat上没有JSON响应。屏幕上出现错误@你的代码有几个问题。一个问题涵盖的内容太多。但首先，您的PHP并不是为了返回
JSONArray
！它被设计为返回一个
JSONObject
。其次，您的PHP代码设计糟糕，而且容易受到SQL注入攻击！在任何时候使用变量筛选结果集时，都应该使用准备好的语句。您应该使用
isset
作为POST参数。当PHP代码因任何原因失败时，应该返回某种格式良好的JSON响应。修复后，我们就可以开始使用Android代码了。。现在我将代码更改为JSONObject，将php更改为isset。但是同样的错误出现了。。我在编码帮助方面很差，这出现在logcat>org.json.JSONException上：status没有值，这是因为您的代码
JSONObject array=new JSONObject（）；Log.i（“测试”，“值：”+array.getString（“状态”））：：您正在创建一个新对象
数组
，但其中没有任何内容！：：您需要编写以下代码：
Log.i（“测试”，“值：”+response.optInt（“状态”，-1））
I/test:value:4 I/test:org.json.JSONException:status没有值看起来状态值是“4”，根据PHP代码，这意味着参数没有正确发送。现在我如何正确发送参数
<?php

// array for JSON response
$response = array();
//set values just in case any thing goes wrong
$response["status"] = 0;
$response["message"] = "Error before start";

// check for post data with isset
if (isset($_POST["Title"])) {

    $title = $_POST["Title"];

    // You were not using PDO so I dumped your connection and require you to provide...
    //...a configuration file for ...
    require_once __DIR__ . '/db_config.php';
    // ...these  variables
    $host = DB_SERVER;
    $db   = DB_DATABASE;
    $user = DB_USER;
    $pass = DB_PASSWORD;
    $charset = 'utf8';

    $dsn = "mysql:host=$host;dbname=$db;charset=$charset";
    $opt = [
        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES   => false,
    ];

    try{
        // connecting to db with PDO
        $pdo = new PDO($dsn, $user, $pass, $opt);


        $sql = 'SELECT isbn, title, authors, accession, publisher, pubyear, pages, rak, hr, vr, barcode
                FROM books 
                WHERE title LIKE :titleParam';

        $titleParam = "%".$title."%";

        $stmt = $pdo->prepare($sql);

        // Bind the parameter
        $stmt->bindParam(':titleParam', $titleParam, PDO::PARAM_STR);

        $res = $stmt->execute();

        if ($res) {
            // success
            $response["status"] = 1;
            // connection node
            $response["books"] = array();

            while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
                $data = array();
                $data["isbn"] = $row["isbn"];
                $data["title"] = $row["title"];
                $data["authors"] = $row["authors"];
                $data["accession"] = $row["accession"];
                $data["publisher"] = $row["publisher"];
                $data["pubyear"] = $row["pubyear"];
                $data["pages"] = $row["pages"];
                $data["rak"] = $row["rak"];
                $data["hr"] = $row["hr"];
                $data["vr"] = $row["vr"];
                $data["barcode"] = $row["barcode"];

                array_push($response["books"], $data);
            }
        }
        else {
            // required field is missing
            $response["status"] = 2;
            $response["message"] = "No data returned";
        }   
    }
    catch (Exception $e){
        $response["status"] = 3;
        $response["message"] = "Error occurred." . $e->getMessage();
    }
}
else {
    $response["status"] = 4;
    $response["message"] = "Post parameters are not correct";
}
// echoing JSON response
echo json_encode($response);
?>