NegativeArraySizeException -1

Question

我正在开发一个通过HTTP调用RESTful服务器的Android应用程序。问题是，我收到以下错误：NegativeArraySizeException -1。我无法弄清为什么问题在发生。

我有两个类：ReadHttpTask和HttpHelper。该错误似乎是由HttpHelper类中的StringBuilder引起的，或者至少是调试器显示异常原因的地方。

ReadHttpTask：

public class ReadHttpTask extends AsyncTask<String, Void, CharSequence> { 
    @Override 
    protected CharSequence doInBackground(String...urls) { 
     String urlString = urls[0]; 
     try{ 
      CharSequence result = HttpHelper.GetHttpResponse(urlString); 
      return result; 
     } catch (IOException ex){ 
      cancel(true); 
      String errorMessage = ex.getMessage() + "\n" + urlString; 
      Log.e("Something went wrong", errorMessage); 
      return errorMessage; 
     } 
    } 
} 

HttpHelper：

public class HttpHelper { 

    public static CharSequence GetHttpResponse(String urlString) throws IOException { 
     URL url = new URL(urlString); 
     URLConnection connection = url.openConnection(); 
     if(!(connection instanceof HttpURLConnection)){ 
      throw new IOException("Not an HTTP connection"); 
     } 

     HttpURLConnection httpConnection = (HttpURLConnection) connection; 
     int responseCode = httpConnection.getResponseCode(); 
     if(responseCode != HttpURLConnection.HTTP_OK){ 
      String responseMessage = httpConnection.getResponseMessage(); 
      throw new IOException("HTTP response code: " + responseCode + " " + responseMessage); 

     } 
     InputStream inputStream = httpConnection.getInputStream(); 
     BufferedReader reader = null; 
     try{ 
      reader = new BufferedReader(new InputStreamReader(inputStream)); 
      StringBuilder result = new StringBuilder(httpConnection.getContentLength()); 
      while(true){ 
       String line = reader.readLine(); 
       if(line==null) break; 
       result.append(line); 
      } 
      return result; 
     } finally { 
      if(reader != null) reader.close(); 
     } 
    } 
} 

Answer 1

您使用从URLConnection的的getContentLength方法创建的StringBuilder的一个实例。

首先，让我们看到的StringBuilder：

StringBuilder public StringBuilder(int capacity)

Constructs a string builder with no characters in it and an initial capacity specified by the capacity argument. Parameters:capacity - the initial capacity. Throws:NegativeArraySizeException - if the capacity argument is less than 0.

如果您打开该文档，您将看到：

Returns

int the content length of the resource that this connection's URL references, -1 if the content length is not known, or if the content length is greater than Integer.MAX_VALUE.

所以，你有你的解决方案。如果您收到一个值，您不应创建具有特定大小的StringBuilder（如果这是-1）。如果没有，让SB管理是自己的大小。

像这样创建的StringBuilder：

StringBuilder result = new StringBuilder(); //create with a size of 16 character.