Java文件读写实现方法详解

import java.io.*;

public class FileReadWrite {
    public static void main(String[] args) {
        String inputFile = "input.txt";
        String outputFile = "output.txt";

        try (FileReader fr = new FileReader(inputFile);
             FileWriter fw = new FileWriter(outputFile)) {

            int ch;
            while ((ch = fr.read()) != -1) {
                fw.write(ch);
            }
            System.out.println("文件复制完成！");
        } catch (IOException e) {
            System.out.println("发生IO异常：" + e.getMessage());
        }
    }
}

import java.io.*;

public class BufferedFileRW {
    public static void main(String[] args) {
        String input = "data.txt";
        String output = "copy_data.txt";

        try (BufferedReader br = new BufferedReader(new FileReader(input));
             BufferedWriter bw = new BufferedWriter(new FileWriter(output))) {

            String line;
            while ((line = br.readLine()) != null) {
                bw.write(line);
                bw.newLine(); // 写入换行符
            }
            System.out.println("文件按行复制完成！");
        } catch (IOException e) {
            System.out.println("读写出错：" + e.getMessage());
        }
    }
}

import java.io.*;

public class BinaryFileCopy {
    public static void main(String[] args) {
        String src = "photo.jpg";
        String dest = "photo_copy.jpg";

        try (FileInputStream fis = new FileInputStream(src);
             FileOutputStream fos = new FileOutputStream(dest)) {

            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = fis.read(buffer)) != -1) {
                fos.write(buffer, 0, bytesRead);
            }
            System.out.println("二进制文件复制成功！");
        } catch (IOException e) {
            System.out.println("文件复制失败：" + e.getMessage());
        }
    }
}

import java.nio.file.*;
import java.util.List;

public class SimpleFileRW {
    public static void main(String[] args) {
        Path input = Paths.get("notes.txt");
        Path output = Paths.get("backup.txt");

        try {
            List lines = Files.readAllLines(input);
            Files.write(output, lines);
            System.out.println("文件写入完成！");
        } catch (IOException e) {
            System.out.println("操作失败：" + e.getMessage());
        }
    }
}