在循环中将文本输入file.txt而不替换文本[重复]

Question

我正在尝试使用缓冲写入器将文本输入记事本，这就是我想出的代码，

import java.util.Scanner;
import java.io.*;
public class FileSample {
    public static void main (String[] args) {
    Scanner sc = new Scanner(System.in);
    String yourtext = " ";
    String fn = "file.txt";
    String choice = " ";
    do{
    try{
        FileWriter fw = new FileWriter(fn);
        BufferedWriter bw = new BufferedWriter(fw);
        System.out.print("Enter text: ");
        yourtext = sc.nextLine(); 
        bw.write(yourtext);
        bw.newLine();

        bw.close();
        System.out.println("===================================");
        System.out.print("Do you still want to continue?:\n [Y]Yes \n [N]No 
      \n::");
        choice = sc.nextLine();
    }catch(IOException ex){
        System.out.println("Error writing to file '" + fn + "'");
    }
    }while(choice.equalsIgnoreCase("Y"));


}
}

所以问题是当用户想要继续并再次输入文本并完成该过程时，应该在 file.txt 中的文本被新输入的文本替换。

Answer 1

您的问题只是您以覆盖模式打开 fileWriter，以使其能够简单地将新文本附加到现有文件，只需将 new FileWriter(fn) 替换为 FileWriter(fn,true) 即可解决。

但是，我也注意到您对资源的处理不当（在我看来），所以我建议您打开 Streams/Reader/Writer 一次，然后在最后关闭它们：

public static void main(String[] args) {
    String yourtext = " ";
    String fn = "file.txt";
    String choice = " ";
    try (Scanner sc = new Scanner(System.in);
            FileWriter fw = new FileWriter(fn);         // making sure to free resources after using them
            BufferedWriter bw = new BufferedWriter(fw);) {
        do {
            System.out.print("Enter text: ");
            yourtext = sc.nextLine();
            bw.write(yourtext);
            bw.newLine();
            System.out.println("===================================");
            System.out.print("Do you still want to continue?:\n [Y]Yes \n [N]No \n::");
            choice = sc.nextLine();
        } while (choice.equalsIgnoreCase("Y"));
    } catch (IOException ex) {
        System.out.println("Error writing to file '" + fn + "'");
    }
}

Answer 2

只需添加 FileWriter(fn,true) 这将保留现有内容并将新内容附加到文件末尾。