Java中PrintWriter使用方法介紹

2022-06-15 14:00:32

簡介

PrintWriter 與 PrintStream 相同。PrintStream 只能接位元組流，而 PrintWriter 既能接位元組流又能接字元流。

PrintStream 最終輸出的總是 byte 資料，而 PrintWriter 則是擴充套件了 Writer 介面，它的 print()/println() 方法最終輸出的是 char 資料。兩者的使用方法幾乎是一模一樣的。

文字檔案的轉碼複製

public class Main {
    public static void main(String[] args) {
        System.out.println("輸入原始檔");
        String s = new Scanner(System.in).nextLine();
        File from = new File(s);
        if (!from.isFile()) {
            System.out.println("請輸入正確的檔案路徑");
            return;
        }
        System.out.println("輸入目標檔案");
        s = new Scanner(System.in).nextLine();
        File to = new File(s);
        if (to.isDirectory()) {
            System.out.println("請輸入具體的檔案路徑，不是目錄路徑");
            return;
        }

        System.out.println("輸入原檔案字元編碼");
        String fromCharset = new Scanner(System.in).nextLine();
        System.out.println("輸入目標檔案字元編碼");
        String toCharset = new Scanner(System.in).nextLine();

        try {
            copy(from, to, fromCharset, toCharset);
            System.out.println("複製成功");
        } catch (Exception e) {
            System.out.println("複製失敗");
        }
    }
    private static void copy(File from, File to, String fromCharset, String toCharset) throws Exception {
        // TODO Auto-generated method stub
        /**
         * 				BufferedReader
         * 			InputStreamReader,fromCharset
         *		FileInputStream
         *	from
         *
         *				PrintWriter
         *			OutputStreamWriter,toCharset
         *		FileOutputStream
         *	to
         *
         *	迴圈按行讀寫
         *
         * */

        BufferedReader in = new BufferedReader(
                new InputStreamReader(
                        new FileInputStream(from), fromCharset));

        PrintWriter out = new PrintWriter(
                new OutputStreamWriter(
                        new FileOutputStream(to), toCharset));

        String line;
        while ((line = in.readLine()) != null) {
            out.println(line);
        }
        in.close();
        out.close();
    }
}