写入和复制文本文件

Question

我有一个任务：编写一个程序，该程序读取一个文件并将该文件的副本写入另一个插入了行号的文件。我不确定在“for(int i =0; i

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Question43 
{
public static void main(String[] args) throws IOException
{
    Scanner fileIn = new Scanner(new File("Chapter 11Assign43.txt") );


    FileWriter fileOut = new FileWriter("FileOut.txt");
    PrintWriter output = new PrintWriter(fileOut);

    String []array = new String[10];

    int indx = 0;
    while(fileIn.hasNext( ) )
    {
        array[indx] = fileIn.nextLine( );
    }

    fileIn.close();

    int num = 1;
    for(int i =0; i < lines.length; i++)
    {
        output.println(num+"\t"+array[i]);
    }
}
}

Answer 1

您可以使用 java.io.LineNumberReader 来计算行数

    LineNumberReader lr = new LineNumberReader(new FileReader("file1"));
    BufferedWriter bw = new BufferedWriter(new FileWriter("file2"));
    String line;
    while((line = lr.readLine()) != null) {
        bw.write(lr.getLineNumber() + " " + line);
        bw.newLine();
    }

Answer 2

想试试这个...

    BufferedReader reader = new BufferedReader(new FileReader("infile"));
    BufferedWriter writer = new BufferedWriter(new FileWriter("outfile"));
    String line;
    int lineNumber = 0;
    while((line = reader.readLine()) != null) {
        writer.write(++lineNumber + " " + line);
        writer.newLine();
    }
    writer.close();
    reader.close();

Answer 3

为什么你不能做类似的事情，

for(int i =0; i < array.length; i++)
{
    output.println(i+"\t"+array[i]);
}

只需使用变量i，因为无论如何它都会随着每个循环递增。