記一次NegativeArraySizeException

問題描述：服務器接收后台返回的報文時，提示java.lang.NegativeArraySizeException

分析：這種異常返回的原因，一般情況下沒有報文提示為返回空報文，初步分析是響應報文流長度出了問題

百度一下類似的情況：https://stackoverflow.com/questions/11207897/negative-array-size-exception

節選部分內容：

try{
     connection = (HttpConnection)Connector.open("http://someurl.xml",Connector.READ_WRITE);
     URLEncodedPostData postData = new URLEncodedPostData(URLEncodedPostData.DEFAULT_CHARSET, false);
     postData.append("username", "loginapi");
     postData.append("password", "myapilogin");
     postData.append("term", word);

     connection.setRequestMethod(HttpConnection.POST);
     connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
     connection.setRequestProperty("User-Agent","Profile/MIDP-2.0 Configuration/CLDC-1.0");
     requestOut = connection.openOutputStream();
     requestOut.write(postData.getBytes());
     String contentType = connection.getHeaderField("Content-type"); 
     detailIn = connection.openInputStream();         
     int length = (int) connection.getLength();
     ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
     if(length > 0){//這里長度沒有判定的情況下，byte array長度若為-1會產生錯誤
         byte info[] = new byte[length];
         int bytesRead = detailIn.read(info);
         while(bytesRead > 0) { 
             baos.write(info, 0, bytesRead); 
             bytesRead = detailIn.read(info); 
             }
         baos.close();
         connection.close();
         requestSuceeded(baos.toByteArray(), contentType);

         detailIn.read(info);
     }
     else
     {
          System.out.println("Negative array size");
     }
           requestOut.close();
           detailIn.close();
           connection.close();
    }

　　結論：HTTP服務器在返回響應報文的時候，沒有進行content.length長度判斷，按照常規流程響應了錯誤長度的報文，導致了接收方報文長度異常