任意のカラムだけ抜き出したCSVファイルのバイト列を作る (OpenCSVを用いた)

gistfile1.java

//import au.com.bytecode.opencsv.CSVReader;
//import au.com.bytecode.opencsv.CSVWriter;

String encoding= "UTF-8";

Reader in = new InputStreamReader(new FileInputStream("/path/to/csvfile.csv"), encoding);
ByteArrayOutputStream ret = new ByteArrayOutputStream();
Writer out = new OutputStreamWriter(ret, encoding);
CSVWriter writer = new CSVWriter(out, ',', '"', '"', "\n");
CSVReader reader = new CSVReader(in);
String[] e;
while ((e = reader.readNext()) != null) {
	writer.writeNext(new String[] {
		e[0]
	});
}
reader.close();
writer.close();

byte[] buf= ret.toByteArray();