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FileReader & FileWriter

讀寫格式：按字符讀寫，每次讀寫一個字符，或者讀寫一個字符數組。

public static void main(String[] args) throws Exception {
    FileReader fread = new FileReader("a.txt");
    FileWriter fwriter = new FileWriter("b.txt");

    int c;
    while ((c = fread.read()) != -1) {
        System.out.print((char) c);

        fwriter.write(c);
    }

    fwriter.flush();
}

使用緩沖流 BufferedReader & BufferedWriter

讀寫格式：按字符讀寫，每次讀寫一個字符，或者讀寫一個字符數組，或者讀寫一個字符串 String。

public static void main(String[] args) throws Exception {
    BufferedReader breader = new BufferedReader(new FileReader("a.txt"));
    BufferedWriter bwriter = new BufferedWriter(new FileWriter("b.txt"));

    String s;
    while ((s = breader.readLine()) != null) {
        System.out.print(s);

        bwriter.write(s);
    }

    bwriter.flush();
}

PrintWriter

public static void main(String[] args) throws Exception {
    PrintWriter pw = new PrintWriter(System.out);

    pw.println("Hello World");

    pw.flush();
}