五、請設計程式從檔案(data.txt)讀入整數資料。若其中有資料重複出現, 僅保留首次出現者,去除第二次以及後續之重複資料。最後,按原順序將資料輸出至檔案 unique.txt。(25 分)

public static void main(String[] args) {
try {
File in = new File("./data.txt");
Scanner scan = new Scanner(in);
Set<Integer> set = new LinkedHashSet<Integer>();
while(scan.hasNextInt()) {
set.add(scan.nextInt());
}
scan.close();
PrintWriter pw = new PrintWriter("unique.txt", "UTF-8");
Integer[] data = set.toArray(new Integer[set.size()]);
for(Integer i : data) {
pw.print(i.toString() + " ");
}
pw.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}