如何在Java中写入File [英] How do I write to File in Java

问题描述

我无法将内容写入java中的文件。请帮助：

I am not able to write the contents to the file in java. Please help:

//Reads an input file containing numbers or strings and sorts them and writes to a new file
import java.io.*;
import java.util.*;

public class FileSort
{
	private Scanner input;
	private Formatter output;
        private List<Integer> list;

	private void openFile(String fileName)
	{
		try{
			input = new Scanner(new File(fileName));
		}

		catch(FileNotFoundException fileNotFoundException)
		{
			System.err.println("Error opening the file. File Not Found");
			System.exit(1);
		}
	}

	private void readFile(String fileName)
	{
		try{
                    list = new ArrayList<Integer>();
                    while(input.hasNext())
                    {
                        list.add(Integer.valueOf(input.next()));
                    }
                    Collections.sort(list);
                    //System.out.printf("\nThe list is: %s",list);
		}
		
		catch(NoSuchElementException elementException)
		{
			System.err.println("File improperly formatted.");
			input.close();
			System.exit(1);
		}
	}

	private void writeFile(String fileName)
	{
		try{
                    output = new Formatter(fileName);
		    output.format("%s", "Hello");
		}
		
		catch(Exception e)
		{
			System.err.println(e.getMessage());
			output.close();
			System.exit(1);
		}
	}
	
	public static void main(String[] args)
	{
		FileSort fs = new FileSort();
		fs.openFile("input.txt");
		fs.readFile("input.txt");
		fs.writeFile("output.txt");
	}
}

推荐答案

参考：

1. 读取，编写和创建文件 [ ^ ]

2. how-to-write-to-file-in-java-bufferedwriter-example [ ^ ]

Refer:
1. Reading, Writing, and Creating Files[^]
2. how-to-write-to-file-in-java-bufferedwriter-example[^]

你没有在writefile中尝试任何文件操作

You are not attempting any file operations in writefile

try{
                    output = new Formatter(fileName);
            output.format("%s", "Hello");
        }

您正在格式化字符串文件名，然后用新字符串覆盖该格式。没有文件操作。



读过这个



http://www.homeandlearn.co.uk/java/write_to_textfile.html [ ^ ]



希望它有所帮助。 />


/ Darren

You are formatting the string filename, then overwriting that format with a new string. No file operations.

Have a read of this

http://www.homeandlearn.co.uk/java/write_to_textfile.html[^]

Hope it helps.

/Darren

您需要使用FileReader和FileWriter。例如：

You need to use FileReader and FileWriter. For example:

try {
            FileWriter writer = new FileWriter("output.txt");
            writer.write("hello");
            writer.flush();
            writer.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

这篇关于如何在Java中写入File的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！