Develop Reference

Problems transforming special characters to bytes and strings

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.

UTF-8 encoding of GET parameters in JSF

I have a search form in JSF that is implemented using a RichFaces 4 autocomplete component and the following JSF 2 page and Java bean. I use Tomcat 6 & 7 to run the application.
...
<h:commandButton value="#{msg.search}" styleClass="search-btn" action="#{autoCompletBean.doSearch}" />
...
In the AutoCompleteBean
public String doSearch() {
//some logic here
return "/path/to/page/with/multiple_results?query=" + searchQuery + "&faces-redirect=true";
}
This works well as long as everything withing the "searchQuery" String is in Latin-1, it does not work if is outside of Latin-1.
For instance a search for "bodø" will be automatically encoded as "bod%F8". However a search for "Kra Ðong" will not work since it is unable to encode "Ð".
I have now tried several different approaches to solve this, but none of them works.
I have tried encoding the searchQuery my self using URLEncode, but this only leads to double encoding since % is encoded as %25.
I have tried using java.net.URI to get the encoding, but gives the same result as URLEncode.
I have tried turning on UTF-8 in Tomcat using URIEncoding="UTF-8" in the Connector but this only worsens that problem since then non-ascii characters does not work at all.
So to my questions:
Can I change the way JSF 2 encodes the GET parameters?
If I cannot change the way JSF 2 encodes the GET parameters, can I turn of the encoding and do it manually?
Am I doing something where strange here? This seems like something that should be supported out-of-the-box, but I cannot find any others with the same problem.

I think you've hit a corner case bug in JSF. The query string is URL-encoded by ExternalContext#encodeRedirectURL() which uses the response character encoding as obtained by ExternalContext#getResponseCharacterEncoding(). However, while JSF by default uses UTF-8 as response character encoding, this is only been set if the view is actually to be rendered, not when the response is to be redirected, so the response character encoding still returns the platform default of ISO-8859-1 which causes your characters to be URL-encoded using this wrong encoding.
I've reported this as issue 2440. In the meanwhile your best bet is to explicitly set the response character encoding yourself beforehand.
FacesContext.getCurrentInstance().getExternalContext().setResponseCharacterEncoding("UTF-8");
Note that this still requires that the container itself uses the same character encoding to decode the request URL, so you certainly need to set URIEncoding="UTF-8" in Tomcat's configuration. This won't mess up the characters anymore as they will be really UTF-8 now.

The only character encoding accepted for HTTP URLs and headers is US-ASCII, you need to URL encode these characters to send them back to the application. Simplest way to do this in java would be:
public String doSearch() {
//some logic here
String encodedSearchQuery = java.net.URLEncoder.encode( searchQuery, "UTF-8" );
return "/path/to/page/with/multiple_results?query=" + encodedSearchQuery + "&faces-redirect=true";
}
And then it should work for any character that you use.

Converting XML to JSON results in unknown characters when running on Centos instead of Windows

I have a Java servlet which gets RSS feeds converts them to JSON. It works great on Windows, but it fails on Centos.
The RSS feed contains Arabic and it shows unintelligible characters on Centos. I am using those lines to encode the RSS feed:
byte[] utf8Bytes = Xml.getBytes("Cp1256");
// byte[] defaultBytes = Xml.getBytes();
String roundTrip = new String(utf8Bytes, "UTF-8");
I tried it on Glassfish and Tomcat. Both have the same problem; it works on Windows, but fails on Centos. How is this caused and how can I solve it?

byte[] utf8Bytes = Xml.getBytes("Cp1256");
String roundTrip = new String(utf8Bytes, "UTF-8");
This is an attempt to correct a badly-decoded string. At some point prior to this operation you have read in Xml using the default encoding, which on your Windows box is code page 1256 (Windows Arabic). Here you are encoding that string back to code page 1256 to retrieve its original bytes, then decoding it properly as the encoding you actually wanted, UTF-8.
On your Linux server, it fails, because the default encoding is something other than Cp1256; it would also fail on any Windows server not installed in an Arabic locale.
The commented-out line that uses the default encoding instead of explicitly Cp1256 is more likely to work on a Linux server. However, the real fix is to find where Xml is being read, and fix that operation to use the correct encoding(*) instead of the default. Allowing the default encoding to be used is almost always a mistake, as it makes applications dependent on configuration that varies between servers.
(*: for this feed, that's UTF-8, which is the most common encoding, but it may differ for others. Finding out the right encoding for a feed depends on the Content-Type header returned for the resource and the <?xml encoding declaration. By far the best way to cope with this is to fetch and parse the resource using a proper XML library that knows about this, for example with DocumentBuilder.parse(uri).)

There are many places where wrong encoding can be used. Here is the complete list http://wiki.apache.org/tomcat/FAQ/CharacterEncoding#Q8

How to check encoding in java?

I am facing a problem about encoding.
For example, I have a message in XML, whose format encoding is "UTF-8".
<message>
<product_name>apple</product_name>
<price>1.3</price>
<product_name>orange</product_name>
<price>1.2</price>
.......
</message>
Now, this message is supporting multiple languages:
Traditional Chinese (big5),
Simple Chinese (gb),
English (utf-8)
And it will only change the encoding in specific fields.
For example (Traditional Chinese),
蘋果
1.3
橙
1.2
.......
Only "蘋果" and "橙" are using big5, "<product_name>" and "</product_name>" are still using utf-8.
<price>1.3</price> and <price>1.2</price> are using utf-8.
How do I know which word is using different encoding?

It looks like whoever is providing the XML is providing incorrect XML. They should be using a consistent encoding.
http://sourceforge.net/projects/jchardet/files/ is a pretty good heuristic charset detector.
It's a port of the one used in Firefox to detect the encoding of pages that are missing a charset in content-type or a BOM.
You could use that to try and figure out the encoding for substrings in a malformed XML file if you can't get the provider to fix their output.

you should use only one encoding in one xml file. there are counterparts of the characters of big5 in the UTF_8 encoding.

Because I cannot get the provider to fix the output, so I should be handle it by myself and I cannot use the extend library in this project.
I only can solve that like this,
String str = new String(big5String.getByte("UTF-8"));
before display the message.

encoding problem in servlet

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).