Question

请查看以下代码

    import java.io.*;
import java.util.ArrayList;
import java.util.List;

public class FileCopy2
{    public static void main(String[]args) 
    {        
        try
        {

              //First in here, we are trying to get the bytes from the file


        File file = new File("D:/burn/preview.mp3"); //The File you need to get

        byte bufferFile[] = new byte[(int)file.length()]; //Creating a byte array, which has the exact size of the file

        BufferedInputStream bi = new BufferedInputStream(new FileInputStream(file));// Creating Buffers for IO

        bi.read(bufferFile, 0, bufferFile.length);//Reading the file

        bi.close();//Closing Buffer




        //Then in here, we are writing those bytes to a text file

        BufferedOutputStream bu = new BufferedOutputStream(new FileOutputStream("C:/Users/Yohan/Desktop/test.txt")); //The output Location
        bu.write(bufferFile, 0, bufferFile.length);//Writing the file
        bu.flush();//Flushing the buffer
        bu.close();//Closing the Buffer

        System.out.println("Done Copieng");



        //Here we are trying to WRITE number of .txt files containing the byte details..In other words, I am breaking the file into peaces

        BufferedReader br = new BufferedReader(new FileReader("C:/Users/Yohan/Desktop/test.txt"));
        BufferedWriter bw = null;

        String content = "";
        int count = 1;
        while((content = br.readLine())!=null)
        {

            bw = new BufferedWriter(new FileWriter("C:/Users/Yohan/Desktop/output4/file"+count+".txt"));
            bw.write(content);
            bw.flush();
            bw.close();


            count++;
            System.out.println("Running");

        }
        System.out.println("-----------------------Done-----------------------------");



            //NOW I NEED TO read all the generated .txt file and create the original file back. How to do it? //
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
}

在那里，首先我获取文件的字节，然后将它们写入文本文件。然后我读取该文本文件，逐行读取，并为每一行生成一个单独的.txt文件。 现在原始程序被分成数千个文件。现在我需要读取所有.txt文件并重新生成.txt文件。我不知道怎么做最后一件事。我怎样才能做到这一点？请帮忙！

Answer 1

如果您想操纵任何类型的文件，请不要认为它们包含文本数据，并将它们视为包含字节的二进制文件。使用输入和输出流读取和写入二进制文件。

这是一个读取文件并将其拆分为写入N个输出文件的1024字节的方法的示例：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileSplit {
    public static void main(String[] args) throws IOException {
        new FileSplit().splitFile(new File(args[0]));
    }

    private void splitFile(File file) throws IOException {
        FileInputStream fis = new FileInputStream(file);
        try {
            byte[] buffer = new byte[1024];
            // remaining is the number of bytes to read to fill the buffer
            int remaining = buffer.length; 
            // block number is incremented each time a block of 1024 bytes is read 
            //and written
            int blockNumber = 1;
            while (true) {
                int read = fis.read(buffer, buffer.length - remaining, remaining);
                if (read >= 0) { // some bytes were read
                    remaining -= read;
                    if (remaining == 0) { // the buffer is full
                        writeBlock(blockNumber, buffer, buffer.length - remaining);
                        blockNumber++;
                        remaining = buffer.length;
                    }
                }
                else { 
                    // the end of the file was reached. If some bytes are in the buffer
                    // they are written to the last output file
                    if (remaining < buffer.length) {
                        writeBlock(blockNumber, buffer, buffer.length - remaining);
                    }
                    break;
                }
            }
        }
        finally {
            fis.close();
        }
    }

    private void writeBlock(int blockNumber, byte[] buffer, int length) throws IOException {
        FileOutputStream fos = new FileOutputStream("output_" + blockNumber + ".dat");
        try {
            fos.write(buffer, 0, length);
        }
        finally {
            fos.close();
        }
    }
}

Java：从.txt文件中读取字节LINE BY LINE

1 个答案: