复制文件，以时间戳为文件名

copy_file.rs

use std::fs;
use std::io;
use std::path::Path;
extern crate time;

fn timestamp() -> f64 {
    let timespec = time::get_time();
    // 1459440009.113178
    let mills: f64 = timespec.sec as f64 + (timespec.nsec as f64 / 1000.0 / 1000.0 / 1000.0);
    mills
}

fn aha() -> io::Result<()> {
    
    let ts = timestamp();
    let ts_str = ts.to_string();
    let v: Vec<&str> = ts_str.split(".").collect();
    let filename = "funny/funny_".to_owned() + v[0] + ".db";
    println!("file name: {}", filename);

    if !Path::new("funny").exists() {
        match fs::create_dir("funny") {
            Ok(o) => println!("{:?}", o),
            Err(err) => println!("{:?}", err),
        }
    }

    fs::copy("D:/data.db", filename)?;
    Ok(())
}

fn main() {
    match aha() {
        Ok(s) => println!("ok: {:?}", s),
        Err(err) => println!("err: {:?}", err),
    }
}