从键盘输入多行字符串（以单行“#”结束输入），存入指定文件，再从文件中读取内容输出到屏幕。

package com.wr.demo;

import java.io.*;

import java.util.ArrayList;

import java.util.List;

import java.util.Scanner;

public class test05 {

    public static void main(String[] args) throws FileNotFoundException {

            // 用于存储用户输入的列表

            List<String> fileContent = new ArrayList<>();

            Scanner scanner = new Scanner(System.in);

            System.out.println("请输入多行字符串（以单行'#'结束输入）: ");

            // 循环获取用户输入

            while (true) {

                String line = scanner.nextLine();

                if (line.equals("#")) {

                    break;

                } else {

                    fileContent.add(line);

                }

            }

            // 将用户输入的内容写入到文件中

            try {

                PrintWriter writer = new PrintWriter("output.txt", "UTF-8");

                for (String str : fileContent) {

                    writer.println(str);

                }

                writer.close();

            } catch (IOException e) {

                e.printStackTrace();

            } catch (Exception e) {

                throw new RuntimeException(e);

            }

        // 从文件中读取内容并输出到屏幕上

            try {

                BufferedReader reader = new BufferedReader(new FileReader("output.txt"));

                String line;

                while ((line = reader.readLine()) != null) {

                    System.out.println(line);

                }

                reader.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

实验运行截图：