Java标准库：如何正确使用文件操作类案例

原创今天药忘吃喽~ 2024-09-16 12:00 73阅读 0赞

在Java标准库中，`java.io`包提供了一系列用于文件和输入/输出流的操作。以下是一个简单的文件操作类案例：

```java
import java.io.File;
import java.io.IOException;

public class FileOperation {
    // 创建新文件
    public void createFile(String fileName) {
        File file = new File(fileName);
        if (!file.exists()) {
            try {
                file.createNewFile();
                System.out.println("File created successfully: " + fileName);
            } catch (IOException e) {
                System.err.println("Error creating file: " + e.getMessage());
            }
        } else {
            System.out.println("File already exists: " + fileName));
        }
    }

// 删除文件
    public void deleteFile(String fileName) {
        File file = new File(fileName);
        try {
            if (file.exists()) {
                file.delete();
                System.out.println("File deleted successfully: " + fileName);
            } else {
                System.out.println("File does not exist: " + fileName));
            }
        } catch (IOException e) {
            System.err.println("Error deleting file: " + e.getMessage());
        }
    }

// 读取文件内容
    public String readFile(String fileName) throws IOException {
        File file = new File(fileName);
        if (file.exists()) {
            try (BufferedReader br = new BufferedReader(new FileReader(file)))) {
                StringBuilder contentBuilder = new StringBuilder();
                String line;
                while ((line = br.readLine())) != null) {
                    contentBuilder.append(line).append("\n");
                }
                return contentBuilder.toString();
            } catch (IOException e) {
                System.err.println("Error reading file: " + e.getMessage());
                throw e;
            }
        } else {
            System.out.println("File does not exist: " + fileName));
            return null;
        }
    }

public static void main(String[] args) {
        FileOperation fileOp = new FileOperation();
        
        // 创建新文件
        fileOp.createFile("test.txt");
        
        // 读取文件内容
        String content = fileOp.readFile("test.txt");
        if (content != null) {
            System.out.println("Content of 'test.txt': " + content);
        } else {
            System.out.println("Error reading 'test.txt': Content not found.");
        }
        
        // 删除文件
        fileOp.deleteFile("test.txt");
    }
}
```

这个案例展示了Java标准库中`java.io`包的几个基本操作：创建新文件，读取文件内容，以及删除文件。