java - 我读取文件然后写入文件，文本之间的空格消失

Question

我正在从临时文件中读取并将其写入永久文件，但字符串在某个地方丢失了所有空格

    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        String b, filename;
        b = null;
        filename = (textfieldb.getText());
        try {
            // TODO add your handling code here:
            dispose();
            Scanner scan;
            scan = new Scanner(new File("TempSave.txt"));
            StringBuilder sb = new StringBuilder();
            while (scan.hasNext()) {
                sb.append(scan.next());
            }
            b = sb.toString();
                    String c; 
        c = b;
        FileWriter fw = null;
        try {
            fw = new FileWriter(filename + ".txt");
        } catch (IOException ex) {
            Logger.getLogger(hiudsjh.class.getName()).log(Level.SEVERE, null, ex);
        }
        PrintWriter pw = new PrintWriter(fw);
        pw.print(c);
        pw.close();
        System.out.println(c);
        } catch (FileNotFoundException ex) {
            Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
        }
          dispose();
        hiudsjh x = new hiudsjh();
        x.setVisible(true);

        System.out.println(b);
    } 

没有错误消息，只是输出应该是一个带有剩余空格的文件

Answer 1

不要使用 hasNext() 和 next() 来获取空格，而是使用 hasNextLine() 和 >nextLine() 逐行读取 filr 并在每行后面附加行分隔符:

while (scan.hasNextLine()) {
    sb.append(scan.nextLine());
    sb.append(System.lineSeparator());
}