I'm showing a dropdown on a web page but when using characters as ○ as options, the dropdown shows a question mark
I'm getting the dropdown option from a SQL Server database in which the column that saves the value is nvarchar type
Then I create an XML output string with the values to send it as response of an AJAX call
When I do xmlWriter.toString() , being xmlWriter a StringWriter object, I'm able to see the ○ character using Eclipse's debug mode but that string needs to be sent as a ByteArrayOutputStream object to add it to response stream for the response to see the XML file on the client side but when doing xmlWriter.toString().getBytes() the ○ character becomes a question mark
I've tried to use xmlWriter.toString().getBytes("UTF-8") but the result is some strange symbols
What am I missing?
By guessing what might be your problem it feels like you're not specifying the encoding in your response object to the browser and it fails guessing the right one. Consider calling getBytes("UTF-8") as you did (better: getBytes(StandardCharsets.UTF_8)) and submit an encoding information along with your response, either in the HTTP header (Content-Type: application/xml; charset=utf-8) as you're probably using HTTP or in the XML header (<?xml version="1.0" encoding="utf-8"?>). Maybe even both as this will provide you the best compatibility.
Related
I have a JSON that looks more or less like this:
{"id":"id","date":"date","csvdata":"csvdata".....}
where csvdata property is a big amount of data in JSON format too.
I was trying to POST this JSON using AJAX in Play! Framework 1.4.x so I sended just like that, but when I receive the data in the server side, the csvdata looks like [object Object] and stores it in my db.
My first thought to solve this was to send the csvdata json in string format to store it like a longtext, but when I try to do this, my request fails with the following error:
413 (Request Entity Too Large)
And Play's console show me this message:
Number of request parameters 3623 is higher than maximum of 1000, aborting. Can be configured using 'http.maxParams'
I also tried to add http.maxParams=5000 in application.conf but the only result is that Play's console says nothing and in my database this field is stored as null.
Can anyone help me, or maybe suggest another solution to my problem?
Thanks you so much in advance.
Is it possible that you sent "csvdata" as an array, not a string? Each element in the array would be a separate parameter. I have sent 100KB strings using AJAX and not run into the http.maxParams limit. You can check the contents of the request body using your browser's developer tools.
If your csvdata originates as a file on the client's machine, then the easiest way to send it is as a File. Your controller action would look like:
public static void upload(String id, Date date, File csv) {
...
}
When Play! binds a parameter to the File type, it writes the contents of the parameter to a temporary file which you can read in. (This avoids running out of memory if a large file is uploaded.) The File parameter type was designed for a normal form submit, but I have used it in AJAX when the browser supported some HTML5 features (File API and Form Data).
I have a simple TCP serversocket that will GET a byte array. This GET comes from when entering a website on this server that contains an img src link to a gif image, the requests looks like this:
GET /myHome.htm HTTP/1.1
GET /house.gif HTTP/1.1
Now the byte array is done like this:
byte[] fileByte = Files.readAllBytes(filePath);
To print the website which contains this image I do this:
out.writeBytes(new String(fileByte));
out:
DataOutputStream out= new DataOutputStream(socketClient.getOutputStream());
Now to make the image display I think I have to use something else then
out.writeBytes()
but I do not know for sure. Anybody knows how to make the image display? Right now the image just dont show at all.
First, make sure your GIF file is not corrupted. (Happened to me before, too).
If that is the case, try this code for sending the GIF file:
byte[] fileByte = Files.readAllBytes(filePath);
writer.writeBytes("HTTP/1.1 200 OK\r\n");
writer.writeBytes("Content-Type: image/gif\r\n");
writer.writeBytes("Content-Length: "+fileByte.length+"\r\n");
writer.writeBytes("\r\n");
writer.write(fileByte, 0, fileByte.length);
And then try to navigate to "house.gif" directly instead of "myHome.htm". Let me know in the comments what this does.
Previous answer attempts:
I think I may have misunderstood your question. Let me try with a different answer:
You are not sure how to figure out on the server when to return the HTML file myHome.htm and when to return house.gif?
I think for this you need to simply parse out the requested URL. Just check whether it contains "house.gif" or not. Then, depending on this, you either return the HTML file as you described above, or you send the .gif file, making sure that you use
writer.write(fileByte, 0, fileByte.length);
to send the binary data and that you set a reply header of
Content-Type: image/gif
In both cases (for the HTML file and the GIF file), though, you should prepend the data you are sending with correct HTTP response headers. Don't take the page-title the wrong way, but this site might help: http://net.tutsplus.com/tutorials/other/http-headers-for-dummies/
And just to make sure: Your server will be receiving TWO independent requests. The first one will ask for the HTML file, the second one will ask for the GIF file. So you send either one or the other. So, there's no "special way" to send the GIF instead of the HTML file. You use the same clientSocket. But it's a different connection.
Previous answer(s):
I think you might be missing the mime-type of your returned data. Try adding the following HTTP header to your reply:
Content-Type: image/gif
Actually... Are you sending a correct HTTP reply at all (including headers, specifically Content-Length)? If not, shoot me a comment and I'll post the code that you need for this.
If, for some reason, you cannot set the content-type header to let the browser know that you are sending it an image, you might be able to load the binary data on the client with an XMLHttpRequest into a JavaScript function rather than specifying it as the source Url of an img tag. Then you can use JavaScript to encode the binary data into a dataURI (http://en.wikipedia.org/wiki/Data_URI_scheme) with the correct mime type and set that as the source of the image.
Actually, I just noticed something in your code:
new String(fileByte)
might interpret the fileBytes as unicode characters rather than binary. Then, when you write this to the writer, it might screw it up as probably not all data in the image are valid unicode. Try replacing the line with this:
writer.write(fileByte, 0, fileByte.length);
Maybe this is all you need to do to fix it???
Hi I have GWT client with standard server-side Servlets.
I can upload file from GWT client-side and read it's contents at server-side
I can send it back to client as String
BUT
I have GWT FormPanel with action (myModule+"import"). FormPanel invokes POST from servlet. Browser then redirects me to myurl/import so I can see contents of uploaded file.
This is not what I wanted though. I'd simply like to have my String back. I added
submitCompleteHandler to my FormPanel, but it doesn't log any results.
I noticed that servlets have method such setContentType so I tried text/html, text/plain ... I don't know what should be there ...
To say it in one sentence, I want to send String back to client from servlet without having browser to redirect me somewhere else. Is it possible?
Since you are submitting a form you get your browser to change navigation. In order to make it work the way you want you have to send the file with ajax. For GWT there is the GWTUpload library that allows you to do that.
If the browser redirects you, it's because you gave a "target" to the FormPanel. By default, it submits within an hidden iframe (a.k.a "ajax upload").
As said in the javadoc, you have to setContentType("text/html") in your servlet if you want onSubmitComplete to be reliably called.
onSubmitComplete's results is the returned HTML's body innerHTML so you have to be very careful when sending back values with < or & in them. The only reliable way to get them back is to escape them on the server-side, and unescape them on the client-side. You can either use your own escaping mechanism, or you can use < and &. In the latter case, to unescape on the client-side, you'd either use String#replace, or create an HTML element, set it's innerHTML with the string you got back, and then get its innerText:
public String htmlUnescape(String htmlEscaped) {
Element tmp = Document.get().createDivElement();
tmp.setInnerHTML(htmlEscaped);
return tmp.getInnerText();
}
On the server-side, you'd use:
escaped = content.replace("&", "&").replace("<", "<")
(order matters here if you don't want <s to become <; also, replacing < and & is enough, > and " won't cause any issue here)
In your case however, make sure first that the file's content is "text" and not "binary", as it wouldn't make sense to return it as String could cause issues depending on how you use the value on the client side.
I have a servlet which receive some parameter from the client ,then do some job.
And the parameter from the client is Chinese,so I often got some invalid characters in the servet.
For exmaple:
If I enter
http://localhost:8080/Servlet?q=中文&type=test
Then in the servlet,the parameter of 'type' is correct(test),however the parameter of 'q' is not correctly encoding,they become invalid characters that can not parsed.
However if I enter the adderss bar again,the url will changed to :
http://localhost:8080/Servlet?q=%D6%D0%CE%C4&type=test
Now my servlet will get the right parameter of 'q'.
What is the problem?
UPDATE
BTW,it words well when I send the form with post.
WHen I send them in the ajax,for example:
url="http://..q='中文',
xmlhttp.open("POST",url,true);
Then the server side also get the invalid characters.
It seems that just when the Chinese character are encoded like %xx,the server side can get the right result.
That's to say http://.../q=中文 does not work,
http://.../q=%D6%D0%CE%C4 work.
But why "http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&q=%E4%B8%AD%E6%96%87&btnG=Google+%E6%90%9C%E7%B4%A2&aq=f&aqi=&aql=&oq=&gs_rfai=" work？
Ensure that the encoding of the page with the form itself is also UTF-8 and ensure that the browser is instructed to read the page as UTF-8. Assuming that it's JSP, just put this in very top of the page to achieve that:
<%# page pageEncoding="UTF-8" %>
Then, to process GET query string as UTF-8, ensure that the servletcontainer in question is configured to do so. It's unclear which one you're using, so here's a Tomcat example: set the URIEncoding attribute of the <Connector> element in /conf/server.xml to UTF-8.
<Connector URIEncoding="UTF-8">
For the case that you'd like to use POST, then you need to ensure that the HttpServletRequest is instructed to parse the POST request body using UTF-8.
request.setCharacterEncoding("UTF-8");
Call this before you access the first parameter. A Filter is the best place for this.
See also:
Unicode - How to get the characters right?
Using non-ASCII characters as GET parameters (i.e. in URLs) is generally problematic. RFC 3986 recommends using UTF-8 and then percent encoding, but that's AFAIK not an official standard. And what you are using in the case where it works isn't UTF-8!
It would probably be safest to switch to POST requests.
I believe that the problem is on sending side. As I understood from your description if you are writing the URL in browser you get "correctly" encoded request. This job is done by browser: it knows to convert unicode characters to sequence of codes like %xx.
So, try to check how do you send the request. It should be encoded on sending.
Other possibility is to use POST method instead of GET.
Do read this article on URL encoding format "www.blooberry.com/indexdot/html/topics/urlencoding.htm".
If you want, you could convert characters to hex or Base64 and put them in the parameters of the URL.
I think it's better to put them in the body (Post) then the URL (Get).
i have html form with textarea in which i paste some XML, for example:
<network ip_addr="10.0.0.0/8" save_ip="true">
<subnet interf_used="200" name="lan1" />
<subnet interf_used="254" name="lan2" />
</network>
When user submit form, that data is send to Java server, so in headers i get something like that:
GET /?we=%3Cnetwork+ip_addr%3D%2210.0.0.0%2F8%22+save_ip%3D%22true%22%3E%0D%0A%3Csubnet+interf_used%3D%22200%22+name%3D%22lan1%22+%2F%3E%0D%0A%3Csubnet+interf_used%3D%22254%22+name%3D%22lan2%22+%2F%3E%0D%0A%3C%2Fnetwork%3E HTTP/1.1
how can i use that in my Java applications? I need to make some calculations on that data and re-send new generated XML.
This answer shows how to use the URLDecoder/URLEncoder classes to decode and encode url strings. It should work if you passed the 'GET' string to the URLDecoders decode method.
To answer your following question (comment)
First you need to extract this xml based response from the url string. Maybe it's enough to create a substring starting with the first < char.
The String should be fed into a XML parser to create a DOM document. The last easy task would be walking through that document and copying the values to your internal network model.
Do not think about using RegExp to extract the data. Use a parser.