Convert Stream to String Java/Groovy

Question

I stole this snippet off the web. But it looks to be limited to 4096 bytes and is quite ugly IMO. Anyone know of a better approach? I'm actually using Groovy btw...

String streamToString(InputStream input) {
        StringBuffer out = new StringBuffer();
        byte[] b = new byte[4096];
        for (int n; (n = input.read(b)) != -1;) {
            out.append(new String(b, 0, n));
        }
        return out.toString();
    }

EDIT:

I found a better solution in Groovy:

InputStream exportTemplateStream = getClass().getClassLoader().getResourceAsStream("export.template")
assert exportTemplateStream: "[export.template stream] resource not found"
String exportTemplate = exportTemplateStream.text

Riduidel · Accepted Answer · 2013-02-07 14:21:25Z

59

Some good and fast answers. However I think the best one is Groovy has added a "getText" method to InputStream. So all I had to do was stream.text. And good call on the 4096 comment.

edited Feb 7, 2013 at 14:21

Riduidel

22.4k15 gold badges91 silver badges193 bronze badges

answered Apr 29, 2011 at 20:54

phil swenson

8,94421 gold badges79 silver badges102 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Anon Over a year ago

So you checked the docs after asking? At least you could paste an example of its use.

phil swenson Over a year ago

I continued looking after I asked of course, I didn't see the .text method at first. Here is the code snippet:InputStream exportTemplateStream = getClass().getClassLoader().getResourceAsStream("export.template") assert exportTemplateStream: "[export.template stream] resource not found" String exportTemplate = exportTemplateStream.text

Anon Over a year ago

fair enough. But as I've said to others: use the variant that takes an explicit character set -- the default character set is rarely what you want.

AechoLiu · Accepted Answer · 2020-09-03 05:09:15Z

17

For Groovy

filePath = ... //< a FilePath object
stream = filePath.read() //< InputStream object

// Specify the encoding, and get the String object
//content = stream.getText("UTF-16") 
content = stream.getText("UTF-8")

The InputStream class reference

The getText() without encoding, it will use current system encoding, ex ("UTF-8").

edited Sep 3, 2020 at 5:09

answered Jan 19, 2016 at 2:40

AechoLiu

18.6k11 gold badges108 silver badges122 bronze badges

Comments

Tomasz Nurkiewicz · Accepted Answer · 2011-04-29 20:57:11Z

8

Try IOUtils from Apache Commons:

String s = IOUtils.toString(inputStream, "UTF-8");

edited Apr 29, 2011 at 20:57

answered Apr 29, 2011 at 20:48

Tomasz Nurkiewicz

342k72 gold badges713 silver badges680 bronze badges

Comments

Afiefh · Accepted Answer · 2011-04-29 20:46:21Z

5

It's reading the input in chunks of 4096 bytes(4KB), but the size of the actual string is not limited as it keeps reading more and appending it to the SringBuffer.

answered Apr 29, 2011 at 20:46

Afiefh

1,1071 gold badge9 silver badges18 bronze badges

Comments

jjnguy · Accepted Answer · 2011-04-29 20:44:58Z

4

You can do it fairly easily using the Scanner class:

String streamToSring(InputStream input) {
    Scanner s = new Scanner(input);
    StringBuilder builder = new StringBuilder();
    while (s.hasNextLine()) {
        builder.append(s.nextLine() +"\n");
    }
    return builder.toString();
}

answered Apr 29, 2011 at 20:44

jjnguy

139k54 gold badges298 silver badges328 bronze badges

5 Comments

Anon Over a year ago

You need to pass a character set or you'll have a hard-to-diagnose bug.

jjnguy Over a year ago

@Anon, this code may have many bugs in it. Code is only presented as an example; not to be used in production.

Anon Over a year ago

@jinguy - does presenting buggy code "improve the internet"? Or simply add to rep?

Anon Over a year ago

@jinguy - if it hurts someone who comes along and takes the highest voted answer as written, I can't see how it would be improving the internet.

jjnguy Over a year ago

@Anon, my point is, people shouldn't be copying code off the internet as written and using it directly in their code.

Anon · Accepted Answer · 2011-04-29 20:51:10Z

2

That snippet has a bug: if the input uses a multi-byte character encoding, there's a good chance that a single character will span two reads (and not be convertable). And it also has the semi-bug that it relies on the platform's default encoding.

Instead, use Jakarta Commons IO. In particular, the version of IOUtils.toString() that takes an InputStream and applies an encoding to it.

answered Apr 29, 2011 at 20:51

Anon

2,33812 silver badges7 bronze badges

Comments

Noah Ternullo · Accepted Answer · 2012-12-04 14:38:01Z

1

For future reviewers who have similar problems, please note that both IOUtils from Apache, and Groovy's InputStream.getText() method require the stream to complete, or be closed before returning. If you are working with a persistent stream you will nead to deal with the "ugly" example that Phil originally posted, or work with non-blocking IO.

answered Dec 4, 2012 at 14:38

Noah Ternullo

6776 silver badges16 bronze badges

Comments

rfranr · Accepted Answer · 2014-12-18 13:14:15Z

0

You can try something similar to this

new FileInputStream( new File("c:/tmp/file.txt") ).eachLine { println it }

answered Dec 18, 2014 at 13:14

rfranr

563 bronze badges

Collectives™ on Stack Overflow

Convert Stream to String Java/Groovy

8 Answers 8

3 Comments

Comments

Comments

Comments

5 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

8 Answers 8

3 Comments

Comments

Comments

Comments

5 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related