Java中的多文件操作：读写、合并等常见问题实例

原创末蓝、 2024-10-12 04:36 59阅读 0赞

在Java中，处理多文件的操作主要包括读写、合并、复制等多种方式。下面是一些具体实例：

1. **读写单个文件**：
```java
import java.io.*;

public class ReadWriteFile {
    public static void main(String[] args) {
        String fileName = "example.txt"; // 要操作的文件名

try (BufferedReader br = new BufferedReader(new FileReader(fileName)))) {
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

// 写入数据
        writeToFile("New Content", fileName);

// 删除文件
        if (exists(fileName)) {
            deleteFile(fileName);
        }
    }

// 读写辅助方法
    private static void writeToFile(String content, String fileName) {
        try (PrintWriter writer = new PrintWriter(new FileWriter(fileName)))) {
            writer.println(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

// 检查文件是否存在
    private static boolean exists(String fileName) {
        File file = new File(fileName);
        return file.exists();
    }

// 删除指定文件
    private static void deleteFile(String fileName) {
        try {
            File file = new File(fileName);
            if (file.delete()) {
                System.out.println("File deleted successfully: " + fileName);
            } else {
                System.out.println("Failed to delete file: " + fileName);
            }
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("Error occurred while deleting the file: " + fileName);
        }
    }
}
```

2. **合并多个文件**：
```java
import java.io.*;
import java.util.*;

public class MergeFiles {
    public static void main(String[] args) {
        // 文件名列表
        List<String> filenames = new ArrayList<>();
        filenames.add("file1.txt");
        filenames.add("file2.txt");

// 创建一个BufferedReader来读取文件内容
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in)));

// 合并文件
        for (String fileName : filenames) {
            try (InputStream inputStream = new FileInputStream(fileName);
                     StringBuilder mergedContent = new StringBuilder()) {

System.out.println("File: " + fileName);

// 读取输入流并将内容添加到mergedContent中
                while ((inputStream.read()) != -1)) {
                    mergedContent.append((char) inputStream.read()));
                }

// 将合并后的内容写入新的文件
                File newFile = new File(fileName + ".merged"));
                try (PrintWriter writer = new PrintWriter(new FileWriter(newFile)))) {
                    writer.println(mergedContent.toString()));
                }
            } catch (IOException e) {
                System.out.println("Error occurred while merging the file: " + fileName);
                e.printStackTrace();
            }
        }

// 询问用户是否继续合并文件
        boolean continueMerge = bufferedReader.readLine().equals("yes") || bufferedReader.readLine().equals("y");
        if (continueMerge) {
            System.out.println("Continuing merge process...");
            mergeFiles(filenames, bufferedReader));
        } else {
            System.out.println("Merge process completed.");
        }
    }

// 递归合并文件
    private static void mergeFiles(List<String> filenames, BufferedReader bufferedReader) {
        if (filenames.size() > 0) {
            String fileName = filenames.remove(0));
            try (InputStream inputStream1 = new FileInputStream(fileName);
                     InputStream inputStream2 = System.in;
                     StringBuilder mergedContent = new StringBuilder()) {

System.out.println("File: " + fileName);

// 读取两个输入流
                while ((inputStream1.read()) != -1) {
                    mergedContent.append((char) inputStream1.read()));
                }

// 从用户那里获取更多的内容
                while ((input(inputStream2)) == -1)) {
                    mergedContent.append((char) input(inputStream2))));
                }

// 如果还有文件需要合并
        if (!filenames.isEmpty()) {
            mergeFiles(filenames, bufferedReader));
        } else {
            System.out.println("Merge process completed.");
        }
    }
}
```

这个例子中，我们处理了多文件的读写、合并等操作。用户可以选择要读写的文件名，并在必要时从键盘输入更多的内容。