generate byte array from StringBuffer.toString

Question

What I'm trying to do is to generate a byte array from a url.

byte[] data = WebServiceClient.download(url);

The url returns json

public static byte[] download(String url) {
    HttpClient client = new DefaultHttpClient();
    HttpGet get = new HttpGet(url);
    try {
        HttpResponse response = client.execute(get);
        StatusLine status = response.getStatusLine();
        int code = status.getStatusCode();
        switch (code) {
            case 200:
                StringBuffer sb = new StringBuffer();
                HttpEntity entity = response.getEntity();
                InputStream is = entity.getContent();
                BufferedReader br = new BufferedReader(new InputStreamReader(is));
                String line;
                while ((line = br.readLine()) != null) {
                    sb.append(line);
                }
                is.close();

                sContent = sb.toString();

                break;       
        }
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    return sContent.getBytes();
}

This data is used as a parameter for String

String json = new String(data, "UTF-8");
JSONObject obj = new JSONObject(json);

for some reason, I get this error

I/global  (  631): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.

I think something there must be missing here sContent = sb.toString(); or here return sContent.getBytes(); but I'm not sure though.

Does the error go away if you do new BufferedReader(new InputStreamReader(is), 8192); ? — durron597
– durron597, Commented Apr 26, 2013 at 13:00
I'd suggest you use the BufferedInputStream to read 4 or 8 kilo bytes chunk of data, rather than dealing with character data and messing with Character sets. — asgs
– asgs, Commented Apr 26, 2013 at 13:01
BTW, you can use a StringBuilder instead a StringBuffer: in a local variable, synchronous operations are not needed — Pablo Lozano
– Pablo Lozano, Commented Apr 26, 2013 at 13:21

rzymek · Accepted Answer · 2013-04-26 13:13:30Z

3

1. Consider using Apache commons-io to read the bytes from InputStream

InputStream is = entity.getContent();
try {
    return IOUtils.toByteArray(is);
}finally{
    is.close();
}

Currently you're unnecessarily converting the bytes to characters and back.

2. Avoid using String.getBytes() without passing the charset as a parameter. Instead use

String s = ...;
s.getBytes("utf-8")

As a whole I'd rewrite you're method like this:

public static byte[] download(String url) throws IOException {
    HttpClient client = new DefaultHttpClient();
    HttpGet get = new HttpGet(url);
    HttpResponse response = client.execute(get);
    StatusLine status = response.getStatusLine();
    int code = status.getStatusCode();
    if(code != 200) {
        throw new IOException(code+" response received.");
    }
    HttpEntity entity = response.getEntity();
    InputStream is = entity.getContent();
    try {
        return IOUtils.toByteArray(is);
    }finally{
        IOUtils.closeQuietly(is.close());
    }
}

edited Apr 26, 2013 at 13:13

answered Apr 26, 2013 at 13:07

rzymek

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1 Comment

Paul Grime Over a year ago

Probably also use IOUtils.closeQuietly().

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