Java UTF-8 encoding not set to URLConnection

问题:

I'm trying to retrieve data from http://api.freebase.com/api/trans/raw/m/0h47

As you can see in text there are sings like this: /ælˈdʒɪəriə/.

When I try to get source from the page I get text with sings like ú etc.

So far I've tried with the following code:

urlConnection.setRequestProperty("Accept-Charset", "UTF-8");
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");

What am I doing wrong?

My entire code:

URL url = null;
URLConnection urlConn = null;
DataInputStream input = null;
try {
url = new URL("http://api.freebase.com/api/trans/raw/m/0h47");
} catch (MalformedURLException e) {e.printStackTrace();}

try {
    urlConn = url.openConnection(); 
} catch (IOException e) { e.printStackTrace(); }
urlConn.setRequestProperty("Accept-Charset", "UTF-8");
urlConn.setRequestProperty("Content-Type", "text/plain; charset=utf-8");

urlConn.setDoInput(true);
urlConn.setUseCaches(false);

StringBuffer strBseznam = new StringBuffer();
if (strBseznam.length() > 0)
    strBseznam.deleteCharAt(strBseznam.length() - 1);

try {
    input = new DataInputStream(urlConn.getInputStream()); 
} catch (IOException e) { e.printStackTrace(); }
String str = "";
StringBuffer strB = new StringBuffer();
strB.setLength(0);
try {
    while (null != ((str = input.readLine()))) 
    {
        strB.append(str); 
    }
    input.close();
} catch (IOException e) { e.printStackTrace(); }

回答1:

The HTML page is in UTF-8, and could use arabic characters and such. But those characters above Unicode 127 are still encoded as numeric entities like ú. An Accept-Encoding will not, help, and loading as UTF-8 is entirely right.

You have to decode the entities yourself. Something like:

String decodeNumericEntities(String s) {
    StringBuffer sb = new StringBuffer();
    Matcher m = Pattern.compile("\\&#(\\d+);").matcher(s);
    while (m.find()) {
        int uc = Integer.parseInt(m.group(1));
        m.appendReplacement(sb, "");
        sb.appendCodepoint(uc);
    }
    m.appendTail(sb);
    return sb.toString();
}

By the way those entities could stem from processed HTML forms, so on the editing side of the web app.

---

After code in question:

I have replaced DataInputStream with a (Buffered)Reader for text. InputStreams read binary data, bytes; Readers text, Strings. An InputStreamReader has as parameter an InputStream and an encoding, and returns a Reader.

try {
    BufferedReader input = new BufferedReader(
            new InputStreamReader(urlConn.getInputStream(), "UTF-8")); 
    StringBuilder strB = new StringBuilder();
    String str;
    while (null != (str = input.readLine())) {
        strB.append(str).append("\r\n"); 
    }
    input.close();
} catch (IOException e) {
    e.printStackTrace();
}

回答2:

Try adding also the user agent to your URLConnection:

urlConnection.setRequestProperty("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.155 Safari/537.36");

This solved my decoding problem like a charm.

回答3:

Well I'm thinking the problem is when you are reading from the stream. You should either call the readUTF method on the DataInputStream instead of calling readLine or, what I would do, would be to create an InputStreamReader and set the encoding, then you can read from the BufferedReader line by line (this would be inside your existing try/catch):

Charset charset = Charset.forName("UTF8");
InputStreamReader stream = new InputStreamReader(urlConn.getInputStream(), charset);
BufferedReader reader = new BufferedReader(stream);
StringBuffer responseBuffer = new StringBuffer();

String read = "";
while ((read = reader.readLine()) != null) {
    responseBuffer.append(read);
}