i don't know really how to formulate this but what i want is to achieve is the following, read a JSON file from a storage (direct url) but if that JSON file does not exist it should return an empty array.
this is what i got so far (and works)
public object GetFromFile(int Code)
{
string uriPath = "http://mystorage.com/folder/" + Code + ".json";
var allText = (new WebClient()).DownloadString(uriPath);
object jsonObject = JsonConvert.DeserializeObject(allText);
return jsonObject;
}
it returns to me the requested list of codes as a array, now if the code does not exists on the storage, possible, then the webservice should just return and empty array []
desired result:
from file (works):
[{001},{002},{003}]
if file does not exist
[]
//The call to WebClient.DownloadString(string) will throw an exception if the
//uri does not exist, in your case, the json file does not exist
var allText = null;
object jsonObject = null;
try
{
allText = (new WebClient()).DownloadString(uriPath);
jsonObject = JsonConvert.DeserializeObject(allText);
}
catch(WebException ex)
{
jsonObject = new object[0];
}
It seems that you expect that the JSON-file contains a sequence of similar items, from the look of it a sequence of integer numbers.
If you already know that the JSON-file contains this type of objects, it is better to use the overload of DeserializeObject<int>.
IEnumerable<int> ReadNumbersFromWebClient(int Code)
{
string uriPath = "http://mystorage.com/folder/" + Code + ".json";
var downloadedText = DownloadText(uriPath);
return JsonConvert.DeserializeObject<int[]>(allText);
}
string DownloadText(string uriPath)
{
using (var webClient = new WebClient())
{
return webClient.DownloadString(uriPath);
}
}
You said that you wanted to return an empty sequence if the "file does not exist". I assume that you meant: "if the web client says there is no string to download"
I looked at WebClient.DownloadString, and I couldn't find what happens if you use an uriPath that does not exist. Do you get empty string, or an exception?
ICollection<int> ReadNumbersFromWebClient(int Code)
{
// in case of exception: return empty string
try
{
string uriPath = "http://mystorage.com/folder/" + Code + ".json";
var downloadedText = DownloadText(uriPath);
return JsonConvert.DeserializeObject<int[]>(allText);
}
catch (Exception exc) // or use specific exception
{
return new int[];
}
}
It would be neater if you let DownloadText catch the expression. In case of exception return empty string. Experiment what happens if you try to Deserialize an empty string. It will probably be an empty int[]
Related
An attempt was made to implement file downloads through the SpringBoot MVC structure. There is no error, it says it has run normally, but the download does not proceed.
All information about the file is entered correctly, and also the path and name of the file are entered correctly.
I'd like to know why the download doesn't proceed even though there's no error.
#RestController
public class Controller {
#PostMapping("/fileDownload")
public void fileDownload(#RequestBody BoardFileDTO dto,HttpServletRequest request,HttpServletResponse response) throws UnsupportedEncodingException {
//File contains all stored paths, names, and extensions
Path fileNamePath = Paths.get(Directory + dto.getFile_save_name()).toAbsolutePath();
String filename = dto.getFile_save_name(); //The name of the saved file
String downname = dto.getFile_name(); //The name of the file to be saved
if (filename == null || "".equals(filename)) {
filename = downname;
}
try {
String browser = request.getHeader("User-Agent");
//File Encoding
if (browser.contains("MSIE") || browser.contains("Trident")
|| browser.contains("Chrome")) {
filename = URLEncoder.encode(filename, "UTF-8").replaceAll("\\+",
"%20");
} else {
filename = new String(filename.getBytes("UTF-8"), "ISO-8859-1");
}
} catch (UnsupportedEncodingException ex) {
System.out.println("UnsupportedEncodingException");
}
System.out.println(fileNamePath);
File file1 = new File(fileNamePath.toString());
if (!file1.exists()) {
return ;
}
// Specifying a File
response.setContentType("application/octer-stream");
response.setHeader("Content-Transfer-Encoding", "binary;");
response.setHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
try {
OutputStream os = response.getOutputStream();
FileInputStream fis = new FileInputStream(fileNamePath.toString());
int ncount = 0;
byte[] bytes = new byte[512];
while ((ncount = fis.read(bytes)) != -1 ) {
os.write(bytes, 0, ncount);
}
fis.close();
os.close();
} catch (FileNotFoundException ex) {
System.out.println("FileNotFoundException");
} catch (IOException ex) {
System.out.println("IOException");
}
}
}
Your code is a bit convoluted imho. A couple of issues I see with your code
Using Path.toString to convert to a File, use the proper factory methods instead or use java.nio.Files to check the existence.
Your content-type is wrong application/octer-stream isn't a known content-type (you probably want application/octet-stream.
Copying from a Path or File is better done with either the StreamUtils from Spring or the java.nio.Files class (if you already have a Path use that).
#PostMapping("/fileDownload")
public void fileDownload(#RequestBody BoardFileDTO dto, HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {
//File contains all stored paths, names, and extensions
Path fileNamePath = Paths.get(Directory, dto.getFile_save_name()).toAbsolutePath();
if (!Files.exists(fileNamePath)) {
return;
}
String filename = determineFilename(dto, request);
// Specifying a File
response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
response.setHeader("Content-Transfer-Encoding", "binary;");
response.setHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
try {
Files.copy(fileNamePath, response.getOutputStream());
} catch (IOException ex) {
System.out.println("IOException");
}
}
private static String determineFilename(BoardFileDTO dto, HttpServletRequest request) {
String filename = dto.getFile_save_name(); //The name of the saved file
if (filename == null || "".equals(filename)) {
filename = dto.getFile_name();
}
String browser = request.getHeader("User-Agent");
//File Encoding
if (browser.contains("MSIE") || browser.contains("Trident") || browser.contains("Chrome")) {
filename = URLEncoder.encode(filename, StandardCharsets.UTF_8).replaceAll("\\+", "%20");
} else {
filename = new String(filename.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
}
return filename;
}
It would write it something like that. As you have a path use the java.nio.Files to check for existence and copying. Use constants for mediatypes and charsets.
Your error handling is quite basic (I would say non-existing and at least not proper) as the processing just stops and returns an empty 200 to the client. No information what so ever.
I took the liberty to factor out the logic to determine the filename, which should make your code more readable.
I want to sort anarray by the object type. So all songs are together, all book are together, and all movies are together.
I am reading a file and determine what each object should be. then creating the object and adding it to the array.
EDIT: Here is the actual code.
static Media[] ReadData()
{
List<Media> things = new List<Media>();
try
{
String filePath = "resources/Data.txt";
string Line;
int counter = 0; // used to check if you have reached the max
number of allowed objects (100)
using (StreamReader File = new System.IO.StreamReader(filePath))
{
while ((Line = File.ReadLine()) != null)
{
This is where each object is created. The file
search for a key word in the beginning of the line, then
creates the corresponding object. It will split the
information on the first line of the object and will
read each line until a "-" character is found and
pass each line into the summary. The summary is then
decrypted and the created object is passed into an
array List. Finally if the array list reaches 100, it
will print "You have reach max number of objects" and
stop reading the file.
if (Line.StartsWith("BOOK"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray){Console.WriteLine(x);} //This is used
for testing
Book tempBook = new Book(tempArray[1],
int.Parse(tempArray[2]), tempArray[3]);
while ((Line = File.ReadLine()) != null)
{
if (Line.StartsWith("-")){break;}
tempBook.Summary = tempBook.Summary + Line;
}
tempBook.Summary = tempBook.Decrypt();
things.Add(tempBook);
counter++;
}
else if (Line.StartsWith("SONG"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray)
{Console.WriteLine(x);} //This is used for testing
Song tempSong = new Song(tempArray[1],
int.Parse(tempArray[2]), tempArray[3], tempArray[4]);
things.Add(tempSong);
counter++;
}
else if (Line.StartsWith("MOVIE"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray)
{Console.WriteLine(x);} //This is used for testing
Movie tempMovie = new Movie(tempArray[1],
int.Parse(tempArray[2]), tempArray[3]);
while ((Line = File.ReadLine()) != null)
{
if (Line.StartsWith("-")) { break; }
tempMovie.Summary = tempMovie.Summary + Line;
}
tempMovie.Summary = tempMovie.Decrypt();
things.Add(tempMovie);
counter++;
}
if (counter == 100)
{
Console.WriteLine("You have reached the maximum number of media
objects.");
break;
}
}
File.Close();
}
}
return things.ToArray(); // Convert array list to an Array and return the
array.
}
In the main code, I have this:
Media[] mediaObjects = new Media[100];
Media[] temp = ReadData();
int input; // holds the input from a user to determin which action to take
for (int i = 0; i<temp.Length;i++){ mediaObjects[i] = temp[i]; }
I want the array of mediaObjects to be sorted by the what type of objects.
I have also used Icomparable to do an arrayList.sort() but still no luck.
public int CompareTo(object obj)
{
if (obj == null)
{
return 1;
}
Song temp = obj as Song;
if (temp != null)
{
//Type is a string
return this.Type.CompareTo(temp.Type);
}
else
{
return 1;
}
}
So I see you have BOOK, SONG and MOVIE types.
This is a classic case of implementing the IComparable interface - although you are correct with the interface name to implement, you are not using this correctly.
Create a base class by the name MediaObject - this will be the main one for your other types of objects you create.
Add the correct properties you need. In this case, the media type is the one in need.
Let this class implement IComparable to help you with the comparison.
override the CompareTo() method in the PROPER way
public class MediaObject : IComparable
{
private string mediaType;
public string MediaType
{
get {return mediaType;}
set {mediaType=value;}
}
public MediaObject(string mType)
{
MediaType = mType;
}
int IComparable.CompareTo(object obj)
{
MediaObject mo = (MediaObject)obj;
return String.Compare(this.MediaType,mo.MediaType); //implement a case insensitive comparison if needed (for your research)
}
}
You can now compare the MediaObject objects In your main method directly.
Thank for the advice. I ended up just reformating how I was creating the list while reading it. I made multiple lists for each object then just happened each one on to the master list so It showed up sorted. I wish I figured that out before I made this long post.
As far as I could find, you can't sort by the type of object in a generic array. If anyone has a better solution feel free to post it.
I've got a simple web api which is consumed from a mvc project, I keep on getting the 'Response status code does not indicate success' and was wondering how would I get the response body from the error, I can see the error within a rest viewer but can't navigate through to the error. This is the following code within the MVC app
public ActionResult Index()
{
try
{
var uri = "http://localhost:57089/api/values";
using (var client = new HttpClient())
{
Task<string> response = client.GetStringAsync(uri);
object result = JsonConvert.DeserializeObject(response.Result);
return (ActionResult) result;
}
}
catch (Exception ex)
{
return Content(ex.ToString());
}
return View();
}
Within the API controller I'm sending a bad request, here's the code
public IHttpActionResult Get()
{
return BadRequest("this is a very bad request " + System.DateTime.Now.ToUniversalTime());
}
I've tried to use WebException, HttpRequestException as exceptions to catch the error with no luck.
I can see the response body within the rest viewer
I want to be able to navigate to the Error Message so I can pass that to the client (which later will be changed to a guid).
[EDITED]
I've got a solution without using GetStringAsync, but wanted to use that if possible.
Here's the solution
var httpClient = new HttpClient();
httpClient.BaseAddress = new Uri(url);
HttpResponseMessage responseMessage = httpClient.GetAsync("").Result;
if (responseMessage.IsSuccessStatusCode) return Content(responseMessage.ToString());
var a = responseMessage.Content.ReadAsStringAsync().Result;
var result = JsonConvert.DeserializeObject<HttpError>(a);
object value = "";
return Content(result.TryGetValue("ErrorMessage", out value) ? value.ToString() : responseMessage.ToString());
Is there a better way?
Using WebException you should be able to get to the ResponseStream and the custom error message like this:
catch (WebException e)
{
var message = e.Message;
using (var reader = new StreamReader(e.Response.GetResponseStream()))
{
var content = reader.ReadToEnd();
}
}
Hope that helps.
I am trying to extract data from below mention json format by pig using jsonLoader():
{"Partition":"10","Key":"618897","Properties2":[{"K":"A","T":"String","V":"M "}, {"K":"B","T":"String","V":"N"}, {"K":"D","T":"String","V":"O"}]}
{"Partition":"11","Key":"618900","Properties2":[{"K":"A","T":"String","V":"W”"},{"K":"B","T":"String","V":"X"}, {"K":"C","T":"String","V":"Y"},{"K":"D","T":"String","V":"Z"}]}
Right now I am able to extract data from “partition” ,“key” and “V” for every array objects with the following code:
A= LOAD '/home/hduser/abc.jon' Using JsonLoader('Partition:chararray,Key:chararray,Properties2:{(K:chararray,T:chararray,V:chararray)},Timestamp:chararray');
B= foreach A generate $0,$1,BagToString(Properties2.V,'\t') as vl:chararray;
store B into './Result/outPut2';
From above code I am getting "Properties2" array value on the sequence basis not column basis, it is creating problem whenever sequence changed or new object comes in existence.
Please help me to extract data on the basis of column( K values.)
My Output
Expected Output
Thanks In Advance
You have two options here
1.Use elephant-bird which will give you a map of key and value.
A = LOAD '/apps/pig/json_sample' USING com.twitter.elephantbird.pig.load.JsonLoader('-nestedLoad') as (json:map[]);
B = FOREACH A GENERATE json#'Partition',json#'Key',json#'Properties2';
dump B;
will give you an output of :
(10,618897,{([T#String,K#A,V#M ]),([T#String,K#B,V#N]),([T#String,K#D,V#O])})
(11,618900,{([T#String,K#A,V#W”]),([T#String,K#B,V#X]),([T#String,K#C,V#Y]),([T#String,K#D,V#Z])})
Or you have to write a custom loader which has to do this
a).It should know what is the correct order of values that will be coming
for the key K
b).Go through each of these values and see if the json is missing any of this key and return an empty/null char for that location.
Am posting the getNext() method of the CustomJsonLoader which will do the same:
#Override
public Tuple getNext() throws IOException {
// TODO Auto-generated method stub
try {
boolean notDone = in.nextKeyValue();
if (!notDone) {
return null;
}
Text value = (Text) in.getCurrentValue();
List<String> valueList = new ArrayList<String>();
if (value != null) {
String jsonString = value.toString();
System.out.println(jsonString);
JSONParser parser = new JSONParser();
JSONObject obj = null;
try {
obj = (JSONObject) parser.parse(jsonString);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("obj is "+obj);
if (obj != null) {
String partition = (String) obj.get("Partition");
String key = (String) obj.get("Key");
valueList.add(partition);
valueList.add(key);
JSONArray innArr = (JSONArray) obj.get("Properties2");
char[] innKeys = new char[] { 'A', 'B', 'C', 'D' };
Map<String,String> keyMap = new HashMap<String,String>();
for (Object innObj : innArr) {
JSONObject jsonObj = (JSONObject) innObj;
keyMap.put(jsonObj.get("K")+"",jsonObj.get("V")+"");
}
for (int i = 0; i < innKeys.length; i++) {
char ch = innKeys[i];
if (keyMap.containsKey(ch+"")) {
valueList.add(keyMap.get(ch+""));
}else{
valueList.add("");
}
}
Tuple t = tupleFactory.newTuple(valueList);
return t;
}
}
return null;
} catch (InterruptedException e) {
}
}
and register it and run :
REGISTER udf/CustomJsonLoader.jar
A = LOAD '/apps/pig/json_sample' USING CustomJsonLoader();
DUMP A;
(10,618897,M,N,,O)
(11,618900,W,X,Y,Z)
Hope this helps!
I have an activity that is being swapped out when I raise an intent for another activity. onPause calls saveState() to save work so far:
private void saveState() {
...
...
if (myUri == null) {
// Inserting a new record
*** myUri = getContentResolver().insert(ContentProvider.CONTENT_URI, values);
} else {
// Update an existing record
getContentResolver().update(myUri, values, null, null);
}
}
Before calling getContentResolver(), ContentProvider.CONTENT_URI = 'content://nz.co.bkd.extraTime.contentprovider/times'.
After the call, myUri = 'times/#' where #=row ID. My question is; where is the 'content:...' prefix to the returned uri?
During the call, ContentResolver.java is called and returns CreatedRow uri
ContentResolver.java
....
....
public final Uri insert(Uri url, ContentValues values)
{
IContentProvider provider = acquireProvider(url);
if (provider == null) {
throw new IllegalArgumentException("Unknown URL " + url);
}
try {
long startTime = SystemClock.uptimeMillis();
*** Uri createdRow = provider.insert(url, values);
long durationMillis = SystemClock.uptimeMillis() - startTime;
maybeLogUpdateToEventLog(durationMillis, url, "insert", null /* where */);
return createdRow;
} catch (RemoteException e) {
// Arbitrary and not worth documenting, as Activity
// Manager will kill this process shortly anyway.
return null;
} finally {
releaseProvider(provider);
}
}
At this point, createdRow = 'times/#'.
The record does actually get saved in the Sqlite database.
Do I have to add the uri prefix in my code or should the full uri be returned?