通过webservice获取404、403错误时如何获取得到的Json Response？

Posted 2023-05-07

【中文标题】通过webservice获取404、403错误时如何获取得到的Json Response？

【英文标题】：How to get the Json Response obtained when getting 404, 403 errors through webservice?

【发布时间】：2018-03-13 12:03:16

【问题描述】：

当我调用 Web 服务时，它会响应 403 和一些类似这样的响应数据。

  "code": "[jwt_auth] invalid_email",
  "message": "Dummy MEssage",
  "data": 
    "status": 403
  

我的代码如下所示

final AsyncTask<Void, String, String> waitForCompletion = new AsyncTask<Void, String, String>() 
            ProgressDialog progressDialog;
            @Override
            protected void onPreExecute()  
               super.onPreExecute();
               //Show Progress
            

            @Override
            public synchronized String doInBackground(Void... params) 
                String res = "";
                String charset = "UTF-8";
                String requestURL = "www.myurl.com";

                try 

                    MultipartUtility multipart = new MultipartUtility(requestURL, charset);

                    multipart.addFormField("username", email);
                    multipart.addFormField("password", password);

                    List<String> response = multipart.finish();
                    for (String line : response) 
                        System.out.println(line);
                        res = line;
                        Log.d("Message" , "Obtained" + response);
                    
                 catch (IOException ex) 
                    System.err.println(ex);
                    dismissProgressDialog(progressDialog);
                
                return res;

            

            @Override
            protected void onPostExecute(String result) 
                dismissProgressDialog(progressDialog);
                if (hasValue(result)) 
                    UserLogin response = (new Gson()).fromJson(result, new TypeToken<UserLogin>() 
                    .getType());

                    if (result.contains("message")) 
                        // Show error message
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) 
                            showMessageAlert(html.fromHtml(response.getMessage(), Html.FROM_HTML_MODE_COMPACT), getString(R.string.app_name), LoginActivity.this);
                         else 
                            showMessageAlert(Html.fromHtml(response.getMessage()), getString(R.string.app_name), LoginActivity.this);
                        
                     else 
                        setUserId(LoginActivity.this , String.valueOf(response.getUserId()));
                        setToken(LoginActivity.this, response.getToken());
                        setLoginInformation(LoginActivity.this, result);
                        Intent intent = new Intent(LoginActivity.this, PickSportsActivity.class);
                        startActivity(intent);
                        finish();
                    
                
            
        ;

问题是当我收到 403 和 404 错误作为响应时，如何获得响应。即使出现这些错误，我如何才能获取得到的响应。

这是我的多部分代码

public class MultipartUtility 
    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;
    StringBuilder result;

    /**
     * This constructor initializes a new HTTP POST request with content type
     * is set to multipart/form-data
     * @param requestURL
     * @param charset
     * @throws IOException
     */
    public MultipartUtility(String requestURL, String charset)
            throws IOException 
        this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";

        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setDoInput(true);
        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        httpConn.addRequestProperty("TOKEN", "Zml0c29vOmZpdHNvb0Aj");
//        httpConn.addRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
       // httpConn.addRequestProperty("content-type", "application/x-www-form-urlencoded");httpConn.setRequestProperty("content-type", "application/x-www-form-urlencoded;  charset=utf-8");
    /*    httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
        httpConn.setRequestProperty("Test", "Bonjour");*/
        outputStream = httpConn.getOutputStream();
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);
    

    /**
     * Adds a form field to the request
     * @param name field name
     * @param value field value
     */
    public void addFormField(String name, String value) 
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
                .append(LINE_FEED);
        writer.append("Content-Type: text/plain; charset=" + charset).append(
                LINE_FEED);
        writer.append(LINE_FEED);
        writer.append(value).append(LINE_FEED);
        writer.flush();


         result = new StringBuilder();
        boolean first = true;
        if (first)
            first = false;
        else
            result.append("&");


        try 
            result.append(URLEncoder.encode(name, "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(value, "UTF-8"));
         catch (UnsupportedEncodingException e) 
            e.printStackTrace();
        
    

    /**
     * Adds a upload file section to the request
     * @param fieldName name attribute in <input type="file" name="..." />
     * @param uploadFile a File to be uploaded
     * @throws IOException
     */
    public void addFilePart(String fieldName, File uploadFile)
            throws IOException 
        String fileName = uploadFile.getName();
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append(
                "Content-Disposition: form-data; name=\"" + fieldName
                        + "\"; filename=\"" + fileName + "\"")
                .append(LINE_FEED);
        writer.append(
                "Content-Type: "
                        + URLConnection.guessContentTypeFromName(fileName))
                .append(LINE_FEED);
        writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
        writer.append(LINE_FEED);
        writer.flush();

        FileInputStream inputStream = new FileInputStream(uploadFile);
        byte[] buffer = new byte[4096];
        int bytesRead = -1;
        while ((bytesRead = inputStream.read(buffer)) != -1) 
            outputStream.write(buffer, 0, bytesRead);
        
        outputStream.flush();
        inputStream.close();

        writer.append(LINE_FEED);
        writer.flush();

        try 
            result.append(URLEncoder.encode(fieldName, "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(fileName, "UTF-8"));
         catch (UnsupportedEncodingException e) 
            e.printStackTrace();
        

    

    /**
     * Adds a header field to the request.
     * @param name - name of the header field
     * @param value - value of the header field
     */
    public void addHeaderField(String name, String value) 
        writer.append(name + ": " + value).append(LINE_FEED);
        writer.flush();
    

    /**
     * Completes the request and receives response from the server.
     * @return a list of Strings as response in case the server returned
     * status OK, otherwise an exception is thrown.
     * @throws IOException
     */
    public List<String> finish() throws IOException 
        List<String> response = new ArrayList<String>();

        writer.append(LINE_FEED).flush();
        writer.append("--" + boundary + "--").append(LINE_FEED);
        writer.close();

        // checks server's status code first
        int status = httpConn.getResponseCode();
        if (status == HttpURLConnection.HTTP_OK) 
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    httpConn.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) 
                response.add(line);
            
            reader.close();
            httpConn.disconnect();
        
        else if(status==500)

            throw new IOException("Server HTTP_INTERNAL_ERROR : " + status);
        else 

            throw new IOException("Server returned non-OK status: " + status);
        

        return response;
    

【问题讨论】：

也发布你的 multipartutility 类。

嗨，我已经添加了我的 Multipart 代码

【参考方案1】：

在您的完成方法代码中查看 int 变量 status。

此状态变量将为您提供从服务器返回的响应代码。

代码中的if 条件检查响应代码200 和500。您可以为此添加自己的逻辑。

您还可以通过使用 StringBuilder 而不是使用 arraylist 作为响应来简化您的完成方法代码。

【讨论】：

这是您正在使用的 MultipartUtility 类中的 finish() 方法public String finish() ... 不，它不是 List<String> response = multipart.finish();

好的，但是当我收到错误代码 403 时，我仍然不知道如何获得这些响应

您在 http_ok​​ 中添加的代码 if case 将与您的其他情况相同。如果您的成功和失败响应具有不同的 json 结构，那么您必须相应地解析它们。