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Rust 文件 I/O 高级应用指南

news 2026/7/23 10:22:53

Rust 文件 I/O 高级应用指南

1. 基本文件操作

在 Rust 中，文件 I/O 操作主要通过std::fs模块来实现。

use std::fs; fn main() -> Result<(), Box<dyn std::error::Error>> { // 读取文件 let content = fs::read_to_string("example.txt")?; println!("File content: {}", content); // 写入文件 fs::write("output.txt", "Hello, World!")?; println!("File written successfully"); Ok(()) }

2. 高级文件操作

2.1 文件元数据

use std::fs; use std::os::unix::fs::MetadataExt; fn main() -> Result<(), Box<dyn std::error::Error>> { let metadata = fs::metadata("example.txt")?; println!("File size: {} bytes", metadata.len()); println!("Is file: {}", metadata.is_file()); println!("Is directory: {}", metadata.is_dir()); println!("Permissions: {:?}", metadata.permissions()); // Unix 特有的元数据 println!("Inode: {}", metadata.ino()); println!("Mode: {:o}", metadata.mode()); Ok(()) }

2.2 目录操作

use std::fs; fn main() -> Result<(), Box<dyn std::error::Error>> { // 创建目录 fs::create_dir("new_dir")?; println!("Directory created"); // 创建多级目录 fs::create_dir_all("parent/child/grandchild")?; println!("Nested directories created"); // 读取目录内容 let entries = fs::read_dir(".")?; for entry in entries { let entry = entry?; let path = entry.path(); if path.is_dir() { println!("Directory: {:?}", path); } else { println!("File: {:?}", path); } } // 删除目录 fs::remove_dir("new_dir")?; println!("Directory deleted"); // 删除多级目录 fs::remove_dir_all("parent")?; println!("Nested directories deleted"); Ok(()) }

2.3 文件权限

use std::fs; use std::fs::Permissions; use std::os::unix::fs::PermissionsExt; fn main() -> Result<(), Box<dyn std::error::Error>> { // 设置文件权限 let mut permissions = Permissions::default(); permissions.set_mode(0o644); // rw-r--r-- fs::set_permissions("example.txt", permissions)?; println!("Permissions set"); // 获取文件权限 let metadata = fs::metadata("example.txt")?; println!("Permissions: {:o}", metadata.permissions().mode()); Ok(()) }

3. 低级文件操作

3.1 使用`File`结构

use std::fs::File; use std::io::{Read, Write}; fn main() -> Result<(), Box<dyn std::error::Error>> { // 打开文件（只读） let mut file = File::open("example.txt")?; let mut content = String::new(); file.read_to_string(&mut content)?; println!("File content: {}", content); // 创建文件（写入） let mut file = File::create("output.txt")?; file.write_all(b"Hello, World!")?; println!("File written successfully"); // 打开文件（追加） let mut file = OpenOptions::new() .append(true) .open("output.txt")?; file.write_all(b"\nAppended content")?; println!("Content appended"); Ok(()) }

3.2 使用`OpenOptions`

use std::fs::OpenOptions; use std::io::Write; fn main() -> Result<(), Box<dyn std::error::Error>> { let mut file = OpenOptions::new() .write(true) .create(true) .truncate(true) .open("output.txt")?; file.write_all(b"Hello, World!")?; println!("File written successfully"); Ok(()) }

4. 异步文件操作

使用tokio::fs模块可以进行异步文件操作。

use tokio::fs; #[tokio::main] async fn main() -> Result<(), Box<dyn std::error::Error>> { // 异步读取文件 let content = fs::read_to_string("example.txt").await?; println!("File content: {}", content); // 异步写入文件 fs::write("output.txt", "Hello, World!").await?; println!("File written successfully"); // 异步创建目录 fs::create_dir("new_dir").await?; println!("Directory created"); // 异步读取目录 let entries = fs::read_dir(".").await?; for entry in entries { let entry = entry?; let path = entry.path(); if path.is_dir() { println!("Directory: {:?}", path); } else { println!("File: {:?}", path); } } Ok(()) }

5. 实际应用场景

5.1 读取大文件

对于大文件，我们可以使用流式读取，避免一次性加载全部内容到内存。

use std::fs::File; use std::io::{BufRead, BufReader}; fn main() -> Result<(), Box<dyn std::error::Error>> { let file = File::open("large_file.txt")?; let reader = BufReader::new(file); for line in reader.lines() { let line = line?; println!("{}", line); } Ok(()) }

5.2 写入大文件

对于大文件，我们可以使用流式写入。

use std::fs::File; use std::io::{BufWrite, BufWriter}; fn main() -> Result<(), Box<dyn std::error::Error>> { let file = File::create("large_output.txt")?; let mut writer = BufWriter::new(file); for i in 0..1000000 { writeln!(writer, "Line {}", i)?; } writer.flush()?; println!("File written successfully"); Ok(()) }

5.3 文件复制

use std::fs; fn main() -> Result<(), Box<dyn std::error::Error>> { fs::copy("source.txt", "destination.txt")?; println!("File copied successfully"); Ok(()) }

5.4 文件重命名

use std::fs; fn main() -> Result<(), Box<dyn std::error::Error>> { fs::rename("old_name.txt", "new_name.txt")?; println!("File renamed successfully"); Ok(()) }