You can construct an InputStreamReader from that InputStream

new InputStreamReader(myInputStream, encoding)

Where myInputStream is your InputStream and encoding is a String that defines the encoding used by your datasource.

You can call your CSVReader like this:

new CSVReader(new InputStreamReader(myInputStream, encoding));

Use

CSVReader reader = new CSVReader(new InputStreamReader(input));

Edit to answer the comment

The problem is because you don't have any constructor for FileReader as you want. See the FileReader API for details. But since you will have to convert the byte stream to character stream so you will have to use InputStreamReader. For better performance you can wrap it with a BufferedReader also

For reading the CSV file, you can use the BufferedReader class:

BufferedReader reader = new BufferedReader(
    new InputStreamReader(new FileInputStream("CSV file location"))
);

After that, use StringTokenizer to read each common separated values from the file, ex.:

if(reader.readLine()!=null) {
    StringTokenizer tokens = new StringTokenizer(

    // this will read first line and separates values by (,) and stores them in tokens.
    (String) reader.readLine(), ",");

    tokens.nextToken(); // this method will read the tokens values on each call.
}

For example, the CSV file is having record of a employee, like:

ram,101

• The first time, the tokens.nextToken() call will return ram.
• The second time, the tokens.nextToken() call will return 101.

Rather than reinventing the wheel you could have a look at OpenCSV which supports reading and writing of CSV files. Here are examples of reading & writing

The code can be simplified and improved in several ways, and the inner loop can be made tighter. Let me show you how:

private static List<List<String>> readTXTFile(String csvFileName) throws IOException {

    String line = null;
    BufferedReader stream = null;
    List<List<String>> csvData = new ArrayList<List<String>>();

    try {
        stream = new BufferedReader(new FileReader(csvFileName));
        while ((line = stream.readLine()) != null) {
            String[] splitted = line.split(",");
            List<String> dataLine = new ArrayList<String>(splitted.length);
            for (String data : splitted)
                dataLine.add(data);
            csvData.add(dataLine);
        }
    } finally {
        if (stream != null)
            stream.close();
    }

    return csvData;

}

• A method should throw an exception as specific as possible, here it's better to use IOException instead of simply Exception
• Whenever possible, return interface types instead of concrete classes. Using List is preferred to using Vector, this allows you the flexibility to change the implementation of the collection later
• Talking about collections: Vector is thread-safe and synchronized in many of its public methods, that can cause a performance hit. If you don't need that, it's better to use ArrayList, it's a drop-in replacement and won't incur in the performance penalty of synchronization.
• There's a simpler way to instantiate a BufferedReader, using a FileReader instead of using an InputStreamReader plus a FileInputStream. Besides, FileReader will take care of pesky details regarding character encoding
• There's a simpler way to add elements to the last List added to csvData, as shown in the code
• There's a simpler way to iterate through the String[] returned by split(), using an enhanced loop
• Don't forget to close your streams! preferably inside a finally block

If you don't need to add more elements to the returned List<List<String>>, you can use the following alternate version. It's faster because it avoids copying the String[] of split elements, but it won't allow adding new elements, as per the contract of asList():

private static List<List<String>> readTXTFile(String csvFileName) throws IOException {

    String line = null;
    BufferedReader stream = null;
    List<List<String>> csvData = new ArrayList<List<String>>();

    try {
        stream = new BufferedReader(new FileReader(csvFileName));
        while ((line = stream.readLine()) != null)
            csvData.add(Arrays.asList(line.split(",")));
    } finally {
        if (stream != null)
            stream.close();
    }

    return csvData;

}