输出日文CSV乱码问题

直接写用Excel打开时会乱码，需要加上下面代码中注释的三行

fos = new FileOutputStream(file, false);

            //fos.write( 0xef );

            //fos.write( 0xbb );

            //fos.write( 0xbf );

            iowriter = new OutputStreamWriter(fos,"UTF-8");

            writer = new CSVWriter(iowriter);