Android调用PHP接口报org.json.JSONException：String无法转JSONObject

算力阿峰

2026-8-2

解决Android调用PHP接口时的JSON转换异常：org.json.JSONException

在开发教育用途的网页爬取应用时，Android端调用PHP接口获取JSON响应并展示，运行时抛出以下异常：

org.json.JSONException: Value Error of type java.lang.String cannot be converted to JSONObject

以下是相关代码及接口返回数据，结合这些信息排查问题并给出解决方案：

错误信息

org.json.JSONException: Value Error of type java.lang.String cannot be converted to JSONObject

Android端调用代码（MainActivity.java）

private void apicall() {
    RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());

    final StringRequest postRequest = new StringRequest(Request.Method.POST, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        JSONObject jsonObject1 = new JSONObject(response);

                        if (jsonObject1.getString("active").equals("0")) {
                            Toast.makeText(MainActivity.this, "Your account temporarily disabled by admin", Toast.LENGTH_SHORT).show();

                            preferences.edit().clear().apply();
                            Intent in = new Intent(getApplicationContext(), login.class);
                            in.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
                            in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            startActivity(in);
                            finish();
                        }

                        if (!jsonObject1.getString("session").equals(getSharedPreferences(constant.prefs, MODE_PRIVATE).getString("session", null))) {
                            Toast.makeText(MainActivity.this, "Session expired ! Please login again", Toast.LENGTH_SHORT).show();

                            preferences.edit().clear().apply();
                            Intent in = new Intent(getApplicationContext(), login.class);
                            in.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
                            in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            startActivity(in);
                            finish();
                        }

                        balance.setText(jsonObject1.getString("wallet"));

                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                            hometext.setText(Html.fromHtml(jsonObject1.getString("homeline"), Html.FROM_HTML_MODE_COMPACT));
                        } else {
                            hometext.setText(Html.fromHtml(jsonObject1.getString("homeline")));
                        }

                        ArrayList<String> name = new ArrayList<>();
                        ArrayList<String> result = new ArrayList<>();

                        JSONArray jsonArray = jsonObject1.getJSONArray("result");
                        for (int a = 0; a < jsonArray.length(); a++){
                            JSONObject jsonObject = jsonArray.getJSONObject(a);

                            name.add(jsonObject.getString("market"));
                            result.add(jsonObject.getString("result"));
                        }

                        adapter_result rc = new adapter_result(MainActivity.this,name,result);
                        recyclerview.setLayoutManager(new GridLayoutManager(MainActivity.this, 2));
                        recyclerview.setAdapter(rc);
                        rc.notifyDataSetChanged();

                        SharedPreferences.Editor editor = preferences.edit();
                        editor.putString("wallet", jsonObject1.getString("wallet")).apply();
                        editor.putString("homeline", jsonObject1.getString("homeline")).apply();
                        editor.putString("code", jsonObject1.getString("code")).apply();
                        is_gateway = jsonObject1.getString("gateway");

                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(MainActivity.this,e.toString(), Toast.LENGTH_SHORT).show();
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    error.printStackTrace();
                    Toast.makeText(MainActivity.this, "Check your internet connection", Toast.LENGTH_SHORT).show();
                }
            }
    ) {
        @Override
        protected Map<String, String> getParams() {
            Map<String, String> params = new HashMap<String, String>();

            params.put("mobile", preferences.getString("mobile", null));
            params.put("session",getSharedPreferences(constant.prefs, MODE_PRIVATE).getString("session", null));

            return params;
        }
    };
    postRequest.setRetryPolicy(new DefaultRetryPolicy(0, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
    requestQueue.add(postRequest);
}

PHP接口代码（home.php）

<?php
include "../connection/config.php";
extract($_REQUEST);

// if(rows(query("select sn from users where mobile='$mobile' and session ='$session'")) == 0){
//     $data['msg'] = "You are not authrized to use this";
      
//     $dd = query("select session,active from users where mobile='$mobile'");
//     $d = fetch($dd);
//     $data['session'] = $d['session'];
//     $data['active'] = $d['active'];
    
//     echo json_encode($data);
//     return;
// }

require_once "../scrap/data/support/web_browser.php";
require_once "../scrap/data/support/tag_filter.php";

$htmloptions = TagFilter::GetHTMLOptions();

$url = "https://dpboss.mobi/";
$web = new WebBrowser();
$result = $web->Process($url);

if (!$result["success"])
{
    echo "Error retrieving URL.  " . $result["error"] . "\n";
    exit();
}

if ($result["response"]["code"] != 200)
{
    echo "Error retrieving URL.  Server returned:  " . $result["response"]["code"] . " " . $result["response"]["meaning"] . "\n";
    exit();
}

$baseurl = $result["url"];

$html = TagFilter::Explode($result["body"], $htmloptions);

$root = $html->Get();
$rows = $root->Find("div.satta-result h4");
$h5rows = $root->Find("div.satta-result h5");


foreach ($rows as $row)
{
    $temp_h4[] = $row->GetInnerHTML();
}
    
foreach ($h5rows as $row)
{
    $temp_h5[] = $row->GetInnerHTML();
}


$get = query("select * from gametime_new");
while($xc = fetch($get))
{
    $time = array_search($xc['market'], $temp_h4);
    $mrk['market'] = $xc['market'];
    $mrk['result'] = $temp_h5[$time];
    $data['result'][] = $mrk;
}

  
$dd = query("select sn,wallet,active,session,code from users where mobile='$mobile'");
$d = fetch($dd);

$nt = query("select homeline from content where sn='1'");
$n = fetch($nt);

if($d['code'] == "0")
{
    $code = $d['sn'].rand(100000,9999999);
    query("update users set code='$code' where mobile='$mobile'");
}
else
{
    $code = $d['code'];
}

if(rows(query("select sn from gateway_config where active='1'")) > 0){
    $data['gateway'] = "1";
} else {
    $data['gateway'] = "0";
}


$data['code'] = $code;
$data['wallet'] = $d['wallet'];
$data['active'] = $d['active'];
$data['session'] = $d['session'];
$data['homeline'] = $n['homeline'];


echo json_encode($data);

接口返回的JSON示例

{"result":[{"market":"SRIDEVI","result":"249-54-356"},{"market":"TIME BAZAR","result":"568-98-279"},{"market":"MILAN DAY","result":"133-74-248"},{"market":"RAJDHANI DAY","result":"123-63-148"},{"market":"KALYAN","result":"266-44-130"},{"market":"SRIDEVI NIGHT","result":"588-11-489"},{"market":"NIGHT TIME BAZAR","result":"258-52-129"},{"market":"MILAN NIGHT","result":"568-98-440"},{"market":"KALYAN NIGHT","result":"447-57-188"},{"market":"RAJDHANI NIGHT","result":"458-76-790"},{"market":"MAIN BAZAR","result":"377-76-367"},{"market":"WORLI MUMBAI","result":"124-70-145"},{"market":"PUNA BAZAR","result":"350-89-379"},{"market":"MILAN MORNING","result":"123-63-148"}],"gateway":"1","code":null,"wallet":null,"active":null,"session":null,"homeline":"WELCOME TO BETPLAY"}

问题排查

异常根源：该异常说明Android端收到的响应不是合法JSON字符串，而是普通文本（比如"Error"开头的错误信息）。查看PHP代码，当爬取外部网站失败时，直接echo错误文本而非JSON，导致解析失败。
潜在隐患：
- 数据库查询用户数据时，若$mobile不存在，$d为空，后续访问$d['code']会触发PHP警告，可能导致输出混乱。
- Android端使用getString()获取可能为null的字段（比如code、wallet），会触发JSONException。

解决方案

1. 统一PHP接口的JSON返回格式

无论成功还是失败，都返回JSON结构，替换原错误处理逻辑：

if (!$result["success"])
{
    $data['error'] = "Error retrieving URL.  " . $result["error"];
    echo json_encode($data);
    exit();
}

if ($result["response"]["code"] != 200)
{
    $data['error'] = "Error retrieving URL.  Server returned:  " . $result["response"]["code"] . " " . $result["response"]["meaning"];
    echo json_encode($data);
    exit();
}

2. 处理PHP中数据库查询为空的情况

在获取用户数据后增加判断，避免后续报错：

$dd = query("select sn,wallet,active,session,code from users where mobile='$mobile'");
$d = fetch($dd);
if(!$d){
    $data['error'] = "用户不存在";
    echo json_encode($data);
    exit();
}

3. Android端优化解析逻辑

增加响应日志打印，方便调试；
先检查响应是否包含错误字段；
使用optString()替代getString()，避免null值触发异常：

@Override
public void onResponse(String response) {
    try {
        Log.d("API_RESPONSE", response); // 打印响应日志
        JSONObject jsonObject1 = new JSONObject(response);
        
        // 检查是否存在错误信息
        if(jsonObject1.has("error")){
            Toast.makeText(MainActivity.this, jsonObject1.getString("error"), Toast.LENGTH_SHORT).show();
            return;
        }

        // 替换getString为optString，避免null值异常
        if (jsonObject1.optString("active", "1").equals("0")) {
            // 原有逻辑...
        }

        String storedSession = getSharedPreferences(constant.prefs, MODE_PRIVATE).getString("session", null);
        if (!jsonObject1.optString("session", "").equals(storedSession) && storedSession != null) {
            // 原有逻辑...
        }

        balance.setText(jsonObject1.optString("wallet", ""));

        // 其他字段同样改用optString
        SharedPreferences.Editor editor = preferences.edit();
        editor.putString("wallet", jsonObject1.optString("wallet", "")).apply();
        editor.putString("code", jsonObject1.optString("code", "")).apply();
        is_gateway = jsonObject1.optString("gateway", "0");

        // 原有列表解析逻辑...

    } catch (JSONException e) {
        e.printStackTrace();
        Toast.makeText(MainActivity.this,"接口返回数据格式错误", Toast.LENGTH_SHORT).show();
    }
}

内容的提问来源于stack exchange，提问作者Nilesh Singh Dahiya

Android调用PHP接口报org.json.JSONException：String无法转JSONObject

错误信息 #

Android端调用代码（MainActivity.java） #

PHP接口代码（home.php） #

接口返回的JSON示例 #

问题排查 #

解决方案 #

1. 统一PHP接口的JSON返回格式 #

2. 处理PHP中数据库查询为空的情况 #

3. Android端优化解析逻辑 #