创建一个程序，从用户获取输入并将其写入输出文件

Question

This is what I have to do:

Create a new copy of the TestFileWriter program called WriterDemo that takes input from the user and writes it into the output file. The program should continue writing lines (a loop may help) until the user supplies an empty line (no text) as their input. Hint: a while loop that has a termination condition that depends on the input string from the user is a good place to start...

The program should be accessed from the terminal and I can't figure out where to put the while loop without ruining the program. The code below is the unmodified version of TestFileWriter. I don't need the full code of WriterDemo, but just some advice on how to use it. An help is greatly appreciated.

import java.io.FileReader;

import java.io.FileWriter;

public class WriterDemo {
public static void main(String args[]){;

FileWriter fout;
    FileReader fin;
    String str;
    int k;
    if(args.length==0){
        System.out.println("Use an argument in the command line");
        System.exit(0);
    }
    try{
        fout = new FileWriter("WrittingProbe.txt");
        for(int i=0; i<args.length; i++){
            fout.write(args[i]);
            fout.write(' ');
        }
        fout.close();

        fin= new FileReader("WrittingProbe.txt");
        System.out.println("The file content is:");
        while((k=fin.read()) !=-1) 
        System.out.println((char)k);
        System.out.println();
        fin.close();

        fout = new FileWriter("WrittingProbe.txt", true);
        str="\nAdded Text\n";
        fout.write(str);
        fout.close();

        fin = new FileReader("WrittingProbe.txt");
        System.out.println("\nNow the file content is:");
        while((k=fin.read()) != -1)
            System.out.print((char)k);
            System.out.println();
            fin.close();

    }
    catch(Exception e){
        System.out.println("Exception: " + e);
    }

}
}

Answer 1

    Scanner scn = new Scanner(System.in);
    ArrayList<String> list = new ArrayList<String>();

    list.add(scn.nextLine());
    for(;!list.get(list.size()-1).equals("");){ //Loops until the last input is a blank line
        list.add(scn.nextLine());

    //Or, you can do it here, as you go, if you want
    }
    //Or here, all at once, using the list

Answer 2

 try (FileWriter fileWriter = new FileWriter("G:\\test.txt")) {
            Scanner scn = new Scanner(System.in);

            while (true) {
                String string = scn.nextLine();

                if (string.equals("0")) {
                    break;
                } else {
                    fileWriter.write(string+"\n");
                }
            }
        }