Reading an InputStream in Java

Question

I'm new to Java thus the question,

I'm using the following class to read a file into a string.

public class Reader {

    public static String readFile(String fileName) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(fileName));
        try {
            StringBuilder sb = new StringBuilder();
            String line = br.readLine();

            while (line != null) {
                sb.append(line);
                sb.append("\n");
                line = br.readLine();
            }
            return sb.toString();
        } finally {
            br.close();
        }
    }

}

How can I modify the method signature of read to read a InputStream as opposed to a string.

YOu mean just send it an `InputStream` and then just do... `BufferedInputStream st = new BufferedInputStream(*PARAMETER*);` ?? — 3kings, Apr 01 '16 at 14:36
Are you looking for `public static String readInputStream(InputStream stream)` or `public static InputStream readFile(String filename)` ? — Shark, Apr 01 '16 at 14:36
Possible duplicate of [Read/convert an InputStream to a String](http://stackoverflow.com/questions/309424/read-convert-an-inputstream-to-a-string) — Landei, Apr 01 '16 at 15:03

kai · Accepted Answer · 2016-04-01T14:49:46.530

Remove the String argument and create an argument of type InputStream. Pass this argument to the constructor of an InputStreamReader and this InputStreamReader can be passed to the constructor of your BufferedReader.

public static String readFile(InputStream is) throws IOException
{
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    .
    .
    .
}

Maybee you want to try a try-with-resource statement. Then you can remove the final block. It looks like this.

public static String readFile(InputStream is) throws IOException
{
    try (BufferedReader br = new BufferedReader(new InputStreamReader(is)))
    {
        StringBuilder sb = new StringBuilder();
        String line = br.readLine();

        while (line != null)
        {
            sb.append(line);
            sb.append("\n");
            line = br.readLine();
        }
        return sb.toString();
    }
}

I had no idea this was so simple. Thanks. – Zeus Apr 01 '16 at 14:40 — Zeus, Apr 01 '16 at 14:40

score 0 · Answer 2 · answered Apr 01 '16 at 14:42

0

If it is not for educational purposes, don't do this manually. E.g. you could use IOUtils.toString from Apache Commons.

answered Apr 01 '16 at 14:42

Landei

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Reading an InputStream in Java

2 Answers2