android - 解析从 .NET Web 服务返回的 JSONArray 时出错

Question

我实现了一个返回 JSON 字符串的 Web 服务，如下所示:

 {"checkrecord":[{"rollno":"abc2","percentage":40,"attended":12,"missed":34}],"Table1":[]}

在我的 Android 应用程序中，我试图将字符串解析为 JSONArray，但我无法这样做，因为我在 logcat 中遇到以下异常:

 11-16 22:15:57.381: ERROR/log_tag(462): Error parsing data org.json.JSONException: Value <?xml of type java.lang.String cannot be converted to JSONArray

如何解决这个问题？

我的安卓代码如下:

public static JSONArray getJSONfromURL(String b)
    {

    //initialize
    InputStream is = null;
    String result = "";
    JSONArray jArray = null;

    //http post
    try{

        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(url);
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();

    }catch(Exception e){
        Log.e("log_tag", "Error in http connection "+e.toString());
    }

    //convert response to string
    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();
        result=sb.toString();
    }catch(Exception e)
             {
        Log.e("log_tag", "Error converting result "+e.toString());
     } 

    //try parse the string to a JSON array
    try{
            jArray = new JSONArray(result);
    }
            catch(JSONException e)
             {
        Log.e("log_tag", "Error parsing data "+e.toString());
     }

    return jArray;
       }

这是返回json的web服务代码

     public class Service1 : System.Web.Services.WebService
{
    [WebMethod]

    public String getdata(String rollno)
    {
        String json;
        try
        {

            using (SqlConnection myConnection = new SqlConnection(@"Data Source=\SQLEXPRESS;Initial Catalog=student;User ID=sa;Password=123"))
            {

                string select = "select * from checkrecord where rollno=\'" + rollno + "\'";
                SqlDataAdapter da = new SqlDataAdapter(select, myConnection);
                DataSet ds = new DataSet();
                da.Fill(ds, "checkrecord");
                DataTable dt = new DataTable();
                ds.Tables.Add(dt);
                json = Newtonsoft.Json.JsonConvert.SerializeObject(ds);

            }
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return null;

        }

        return json;

    }

Answer 1

您的结果最初不是 JSONArray，而是 JSONObject。

试试这个:

JSONObject jsonResult = new JSONObject(new String(reader));

JSONArray jArray = jsonResponse.getJSONArray("checkrecord");