Java JSON Android解析数据时出错

请注意，我的JSON Web服务有问题。调用函数时，出现以下异常：

03-19 15:14:10.013: E/JSON Parser(12011): Error parsing data org.json.JSONException: End of input at character 0 of 
03-19 15:14:10.013: W/System.err(12011): java.util.concurrent.ExecutionException: java.lang.NullPointerException
03-19 15:14:10.013: W/System.err(12011):    at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:223)
03-19 15:14:10.013: W/System.err(12011):    at java.util.concurrent.FutureTask.get(FutureTask.java:82)
03-19 15:14:10.013: W/System.err(12011):    at android.os.AsyncTask.get(AsyncTask.java:482)
03-19 15:14:10.013: W/System.err(12011):    at dp.zajac.facerecognizer3.FromCameraMainSceneFragment.uploadFaceToServer(FromCameraMainSceneFragment.java:657)
03-19 15:14:10.013: W/System.err(12011):    at dp.zajac.facerecognizer3.FromCameraMainSceneFragment.onSingleFaceDialogPositiveClickWithDatabases(FromCameraMainSceneFragment.java:635)
03-19 15:14:10.013: W/System.err(12011):    at dp.zajac.savefacesdialogs.FaceToSaveDialog$3.onClick(FaceToSaveDialog.java:162)
03-19 15:14:10.013: W/System.err(12011):    at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
03-19 15:14:10.013: W/System.err(12011):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-19 15:14:10.013: W/System.err(12011):    at android.os.Looper.loop(Looper.java:137)
03-19 15:14:10.013: W/System.err(12011):    at android.app.ActivityThread.main(ActivityThread.java:4830)
03-19 15:14:10.013: W/dalvikvm(12011): threadid=13: thread exiting with uncaught exception (group=0x416742a0)
03-19 15:14:10.023: W/System.err(12011):    at java.lang.reflect.Method.invokeNative(Native Method)
03-19 15:14:10.023: W/System.err(12011):    at java.lang.reflect.Method.invoke(Method.java:511)
03-19 15:14:10.023: W/System.err(12011):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
03-19 15:14:10.023: W/System.err(12011):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
03-19 15:14:10.023: W/System.err(12011):    at dalvik.system.NativeStart.main(Native Method)
03-19 15:14:10.033: W/System.err(12011): Caused by: java.lang.NullPointerException
03-19 15:14:10.033: W/System.err(12011):    at dp.fedorko.client.jsonClient.doInBackground(jsonClient.java:58)
03-19 15:14:10.033: W/System.err(12011):    at dp.fedorko.client.jsonClient.doInBackground(jsonClient.java:1)
03-19 15:14:10.043: W/System.err(12011):    at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-19 15:14:10.043: W/System.err(12011):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
03-19 15:14:10.043: W/System.err(12011):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
03-19 15:14:10.043: W/System.err(12011):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
03-19 15:14:10.043: W/System.err(12011):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
03-19 15:14:10.043: W/System.err(12011):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
03-19 15:14:10.043: W/System.err(12011):    at java.lang.Thread.run(Thread.java:856)

我使用此代码调用JSON web服务：

 protected String doInBackground(Object... params) {
        if((Integer)params[0]==0)
            return null;
        if((Integer)params[0]==1){
            // Building Parameters
            List<NameValuePair> params1 = new ArrayList<NameValuePair>();
            params1.add(new BasicNameValuePair("name", "mobilefirst"));
            //params1.add(new BasicNameValuePair("vector", "0 1 2 1 0"));
            //params1.add(new BasicNameValuePair("personid", "1"));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params1);
            Log.d("Create Response", json.toString());
            return json.toString();
        }
        return null;
    }

<?php
 //require_once __DIR__ . '/php_connect.php';
/*
 * Following code will create a new product row
 * All product details are read from HTTP Post Request
 */

// array for JSON response
$response = array();

// check for required fields
if (isset($_POST['name']) /* && isset($_POST['vector']) && isset($_POST['personid'])*/) {

    $name = $_POST['name'];
    //$vector = $_POST['vector'];
    //$personid = $_POST['personid'];

    // include db connect class
    require_once __DIR__ . '/php_connect.php';

    // connecting to db
    $db = new DB_CONNECT();

    // mysql inserting a new row
    $result = mysql_query("INSERT INTO person(name) VALUES('$name')");

    // check if row inserted or not
    if ($result) {
        // successfully inserted into database
        $response["success"] = 1;
        $response["message"] = "User successfully created.";

        // echoing JSON response
        echo json_encode($response);
    } else {
        // failed to insert row
        $response["success"] = 0;
        $response["message"] = "Oops! An error occurred.";

        // echoing JSON response
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);
}
?>

受保护字符串doInBackground（对象…参数）{
如果（（整数）参数[0]==0）
返回null；
if（（整数）参数[0]==1）{
//建筑参数
List params1=new ArrayList（）；
参数1.add（新的BasicNameValuePair（“名称”、“mobilefirst”）；
//参数1.add（新的BasicNameValuePair（“向量”，“0 1 2 1 0”））；
//参数1.add（新的BasicNameValuePair（“personid”，“1”））；
//获取JSON对象
//请注意，创建产品url接受POST方法
JSONObject json=jsonParser.makeHttpRequest（url\u create\u product，
“职位”，参数1）；
d（“创建响应”，json.toString（））；
返回json.toString（）；
}
返回null；
}

这是jsonParser代码：

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    // function get json from url
    // by making HTTP POST or GET mehtod
    public JSONObject makeHttpRequest(String url, String method,
            List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }           

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

公共类JSONParser{
静态InputStream为空；
静态JSONObject jObj=null；
静态字符串json=“”；
//建造师
公共JSONParser（）{
}
//函数从url获取json
//通过使用HTTP POST或GET方法
公共JSONObject makeHttpRequest（字符串url、字符串方法、，
列表参数）{
//发出HTTP请求
试一试{
//检查请求方法
如果（方法==“POST”）{
//请求方法为POST
//defaultHttpClient
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
HttpPost HttpPost=新的HttpPost（url）；
setEntity（新的UrlEncodedFormEntity（参数））；
HttpResponse HttpResponse=httpClient.execute（httpPost）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
}else if（方法==“GET”）{
//请求方法是GET
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
String paramString=URLEncodedUtils.format（params，“utf-8”）；
url+=“？”+参数字符串；
HttpGet HttpGet=新的HttpGet（url）；
HttpResponse HttpResponse=httpClient.execute（httpGet）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
}           
}捕获（不支持的编码异常e）{
e、 printStackTrace（）；
}捕获（客户端协议例外e）{
e、 printStackTrace（）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}
试一试{
BufferedReader reader=新的BufferedReader（新的InputStreamReader(
is，“iso-8859-1”），8）；
StringBuilder sb=新的StringBuilder（）；
字符串行=null；
而（（line=reader.readLine（））！=null）{
sb.追加（第+行“\n”）；
}
is.close（）；
json=sb.toString（）；
}捕获（例外e）{
Log.e（“缓冲区错误”，“错误转换结果”+e.toString（））；
}
//尝试将字符串解析为JSON对象
试一试{
jObj=新的JSONObject（json）；
}捕获（JSONException e）{
Log.e（“JSON解析器”，“错误解析数据”+e.toString（））；
}
//返回JSON字符串
返回jObj；
}
}

这是我的web服务代码：

 protected String doInBackground(Object... params) {
        if((Integer)params[0]==0)
            return null;
        if((Integer)params[0]==1){
            // Building Parameters
            List<NameValuePair> params1 = new ArrayList<NameValuePair>();
            params1.add(new BasicNameValuePair("name", "mobilefirst"));
            //params1.add(new BasicNameValuePair("vector", "0 1 2 1 0"));
            //params1.add(new BasicNameValuePair("personid", "1"));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params1);
            Log.d("Create Response", json.toString());
            return json.toString();
        }
        return null;
    }

<?php
 //require_once __DIR__ . '/php_connect.php';
/*
 * Following code will create a new product row
 * All product details are read from HTTP Post Request
 */

// array for JSON response
$response = array();

// check for required fields
if (isset($_POST['name']) /* && isset($_POST['vector']) && isset($_POST['personid'])*/) {

    $name = $_POST['name'];
    //$vector = $_POST['vector'];
    //$personid = $_POST['personid'];

    // include db connect class
    require_once __DIR__ . '/php_connect.php';

    // connecting to db
    $db = new DB_CONNECT();

    // mysql inserting a new row
    $result = mysql_query("INSERT INTO person(name) VALUES('$name')");

    // check if row inserted or not
    if ($result) {
        // successfully inserted into database
        $response["success"] = 1;
        $response["message"] = "User successfully created.";

        // echoing JSON response
        echo json_encode($response);
    } else {
        // failed to insert row
        $response["success"] = 0;
        $response["message"] = "Oops! An error occurred.";

        // echoing JSON response
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);
}
?>

---

您的JSON数据不完整或格式不正确。在构造之前先验证。不要相信来源。
使用
sb.append（行）而不是
sb.append（行+“\n”）在转换为JSONObject之前也要记录json，以检查是否从服务器获取有效的json字符串？我如何记录此json？@ρ∑ѕρK如何记录此json？只需添加
log.e（“缓冲区错误”，“json响应”+json）在转换为JSONObject@ρ∑ρѕρєK之前，我不确定将此代码放置在何处…它意味着什么？哪里有问题？@MartinFedyFedorko您接收的json数据无效或损坏。