我有一个大的csv文件，大小为6gb，逗号分隔。下面是mapper函数

@Override
    public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        String[] tokens = value.toString().split(",");

        String crimeType = tokens[5].trim();      // column #5 is the crime type in the CSV file, serving key
//      int year = Integer.parseInt(tokens[17].trim()); // the year when the crime happened

        int year = 2010;

        CrimeTypeKey crimeTypeYearKey = new CrimeTypeKey(crimeType, year);

        context.write(crimeTypeYearKey, ONE);
}

如您所见，我使用“.split”来分解每一行（或列？）。我想知道在这种情况下如何使用opencsv？请给我举个例子，非常感谢