在Java中，尝试逐行读取文本并将每行写入输出文件

我试图从一个文本文件中读取数据（一行一行），我想将从苍蝇中读取的数据写入输出文件

下面是我如何编程我的代码：

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;


public class read {

    public static void main(String args[])
    {
        String input = null;
        input = readFile();
        writeFile(input);

    }
    public static void writeFile(String in)
    {
        String fileName = "output.txt";
    //String payload = null;
     try {
        FileWriter fw = new FileWriter(fileName);
        BufferedWriter bw =new BufferedWriter(fw);  
        bw.write(in);                       
        System.out.println("Received "+in.length()+" bytes: ");  
        bw.close();
     }
     catch(IOException ex) {
        System.out.println("Error writing to file '"+ fileName + "'");
     }

    }


    public static String readFile()
    {
        String fileName = "temp.txt";
        String line = null;
        String Sentence = null;
        try {            
        FileReader fr = new FileReader(fileName);
        BufferedReader br = new BufferedReader(fr);
        while((line = br.readLine()) != null) {
            //Sentence += line+'\n';
            Sentence = line +'\n';
        }
        br.close();
        System.out.println("Sending file "+fileName);
        return Sentence;
        }
        catch(FileNotFoundException ex) {
            System.out.println(
                "Unable to open file '" + 
                fileName + "'"); 
            return null;
        }
        catch(IOException ex) {
            System.out.println(
                "Error reading file '" 
                + fileName + "'");   
            return null;
        // Or we could just do this: 
        // ex.printStackTrace();
        }
    }
    }

文本文件： 那天大约三点钟，我从城里回来 梅对生活相当厌恶。 我在这个古老的国家呆了三个月，现在 受够了

输出： read方法从文本文件中读取第一行，并将该行写入输出文件

---

我是编程新手，非常感谢您的帮助

要创建输出文件，请尝试以下操作：

PrintWriter writer = new PrintWriter(filename, "UTF-8");
writer.println(in);
writer.close();

当您从文件中读取时，您应该通过执行以下操作将行附加到原始变量

Sentence += line+'\n';