[读取文件时保持换行符

Question

我想读取文件并对其进行修改，但是每当创建新文件时，所有内容都保持一行。因此，我的问题是如何在不删除换行符的情况下保留换行符？

public class JavaProgram {

    public static char[] caesar (int offset, char [] charArray) {
        char [] size = new char [charArray.length];

        for (int i = 0; i < charArray.length; i++) {
            int crypt = (charArray[i] + offset);
            size[i] = (char) (crypt);
        }
        return size;
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String text = "";
        StringBuilder convert = new StringBuilder();
        Scanner keyboard = new Scanner (System.in);

        File file = new File ("C:\\Users\\starfleet\\Desktop\\laboratory\\Java\\1DV506 - Problem Solving and Programming\\kk222sy_assignment4\\document.txt");

            try {
                Scanner input = new Scanner (file);
                while (input.hasNextLine()) {
                        text = input.nextLine();

                        char [] arr = text.toCharArray();
                        char [] newArr = encrypt(3, arr);

                        for (int i = 0; i < newArr.length; i++) {
                            convert.append(newArr[i]);
                } catch (IOException e) {
                    e.printStackTrace(); 
                }
                try {
                    // write file
                    PrintWriter printer = new PrintWriter (document);

                    printer.append(convert);
                    printer.close();

                } catch (IOException e) {
                    e.printStackTrace();
                }

Answer 1

在写每一行时添加换行符。您的情况是在for循环后追加了加密字符：

for (int i = 0; i < newArr.length; i++) {
       convert.append(newArr[i]);
convert.append("\r\n");

[在Java中添加新行就像在字符串的末尾包含“ \ n”，“ \ r”或“ \ r \ n”一样简单，具体取决于您所使用的SO。