编写一个程序，将一个文本文件的内容按行读出，每读出一行就顺序加上行号，并写入到另一个文件中。

浅浅的花香味﹌ 2022-12-21 10:53 250阅读 0赞

实验九 Java 语言的输入输出与文件处理
    实验目的
    1．了解流式输入输出的基本原理。
    2．掌握 File、FileInputStream、FileOutputStream 类的使用方法。
    3．掌握 FileReader、FileWriter、BufferedReader 类的使用方法。
    主要仪器设备及耗材
    安装了 JDK1.8 的 PC 一台
    实验内容
    2. 编写一个程序，将一个文本文件的内容按行读出，每读出一行就顺序加上行号，并写入
    到另一个文件中。

![20201116104918210.png][]

src/com/temp/ShowLineNumBeforEachLine.java

package com.temp;
    
    import java.io.*;
    
    /**
     * @Author lanxiaofang
     * @email 983770299@qq.com
     * @date 2020/11/16 9:18
     */
    public class ShowLineNumBeforEachLine {
    
        private final static String url_1 = "D://word1.txt";
        private final static String url_2 = "D://word2.txt";
    
        //use BufferedReader and BufferedWriter
        public static void main(String[] args) {
    
            useBufferedWriter(url_1, url_2);
    
        }
    
        
        /**
         * useBufferedWriter
         *
         * @param from_url,to_url Copy the contents from the file in path from_url to the file in path to_url
         *                        Read a line, add line num before the line and write the line, and then create a new line
         */
        public static int useBufferedWriter(String from_url, String to_url) {
            String thisLine;
            int count = 0;
            try {
                FileReader fileReader = new FileReader(from_url);
                FileWriter fileWriter = new FileWriter(to_url);
                BufferedReader bufferedReader = new BufferedReader(fileReader);
                BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
                while ((thisLine = bufferedReader.readLine()) != null) {
                    count++;
                    System.out.println(thisLine);
                    System.out.println(count+" "+thisLine);
                    bufferedWriter.write(count+" "+thisLine);
                    bufferedWriter.newLine();
                }
                bufferedWriter.flush();
                System.out.println("--useBufferedWriter-- had read " + count + " lines. \n--useBufferedWriter-- had writer "+count+" lines.");
            } catch (IOException e) {
                e.printStackTrace();
                return 0;
            }
            return 1;
        }
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NfbGFueGlhb2Zhbmc_size_16_color_FFFFFF_t_70][]

[20201116104918210.png]: /images/20221120/4f47c48772d5400597bc524d32172703.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NfbGFueGlhb2Zhbmc_size_16_color_FFFFFF_t_70]: /images/20221120/6d0c5693f9254b399c8be56d94655ce0.png