Question

我想检查给定的URL是否提供JSON内容。我怎么能做到这一点？我正在使用以下方法从URL读取JSON。我没有得到任何关于这个主题的答案。我需要帮助来实现这一目标。

public JSONObject getJSONFromUrl(String url) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        StatusLine statusLine = httpResponse.getStatusLine();
        int statusCode = statusLine.getStatusCode();
        if (statusCode == 200) {
            resultOk=true;
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
            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();
                jsonString = sb.toString();
            } catch (Exception e) {
                Log.e("Buffer Error",
                        "Error converting result " + e.toString());
            }
        } else {
            resultOk=false;
        }
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

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

Answer 1

您可以检查您的回复字符串。如果它以“{”或“[”字符开头，则表示响应采用json格式。

Answer 2

try {
        jsonObjects = new JSONObject(jsonString);
} catch (JSONException e) {
    Log.e("JSON Parser", "Error parsing data " + e.toString());
}

这本身应该足以测试你是否真的有JSON。

如果没有，则应该提出异常。只是检查你收到的字符串是否以“{”开头并不是真的有任何迹象： {这是无效的JSON ..}

Answer 3

[已关闭]我通过更改并检查“resultOk”标志得到了正确的解决方案。在这里：

public JSONObject getJSONFromUrl(String url) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        StatusLine statusLine = httpResponse.getStatusLine();
        int statusCode = statusLine.getStatusCode();
        if (statusCode == 200) {
            resultOk = true;
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
            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();
                jsonString = sb.toString();
                jsonObjects = new JSONObject(jsonString);
            } catch (IOException e) {
                Log.e("Buffer Error",
                        "Error converting result " + e.toString());
            } catch (JSONException e) {
                resultOk = false;
                Log.e("JSON Parser", "Error parsing data " + e.toString());
            }
        } else {
            resultOk = false;
        }
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return jsonObjects;
}

来自部分：

if (JSONObjectParser.resultOk){
    //Show Success dialog with some good message
    //And rest of the code....  
} else{
    //Show Error dialog with some error message
    //And rest of the code....
}

最后这个对我来说很好。谢谢你...

Answer 4

这是有效的json格式

{
"ECom": "",
"EDept": "01",
"EFlr": "GF",
"EComId": "",
"EDeptId": "01",
"EFlrId": "GF",
"EName": "EMPLOYEE 1",
"ECode": "00000001",
"VId": "201200000002",
"VName": "",
"VComp": "",
"VAddr": "",
"VMob": "",
"VEmail": "",
"VContact": "",
"VCat": "3",
"VPurpose": "1",
"VLaptop": "LAPTOP",
"VBel": "",
"VGender": "M",
"VRmk1": "",
"VRmk2": "",
"NOV": ""
}

确保URL是否提供JSON

4 个答案: