Node.js fs.fstat() 方法

fs.fstat() 方法用于返回有关给定文件描述符的信息。返回的 fs.Stat 对象有几个字段和方法来获取有关文件的更多详细信息。

句法：

fs.fstat( fd, options, callback )

参数：此方法接受三个参数，如上所述，如下所述：

• fd：它是一个整数，表示该方法使用的文件描述符。
• options：它是一个对象，可用于指定将影响输出的可选参数。它有一个可选参数：
  • bigint：它是一个布尔值，指定 fs.Stats 对象中返回的数值是否为 bigint。默认值为假。
• callback：方法执行时调用的函数。
  • err：如果该方法会抛出一个错误
  • Stats：它是包含文件路径详细信息的 Stats 对象。

下面的示例说明了 Node.js 中的fs.fstat() 方法：

示例 1：此示例使用 fs.fstat() 方法获取文件和目录的详细信息。

// Node.js program to demonstrate the
// fs.fstat() method
  
// Import the filesystem module
const fs = require('fs');
  
// Define the file descriptor for a file
let file_fd = fs.openSync('example_file.txt', 'r');
  
// Getting information for a file
fs.fstat(file_fd, (error, stats) => {
  if (error) {
    console.log(error);
  }
  else {
    console.log("Stats object for: example_file.txt");
    console.log(stats);
  
    // Using methods of the Stats object
    console.log("Path is file:", stats.isFile());
    console.log("Path is directory:", stats.isDirectory());
  }
});
  
// Define the file descriptor for a folder
let dir_fd = fs.openSync('example_directory', 'r');
  
// Getting information for a directory
fs.fstat(dir_fd, (error, stats) => {
  if (error) {
    console.log(error);
  }
  else {
    console.log("Stats object for: example_directory.txt");
    console.log(stats);
  
    // Using methods of the Stats object
    console.log("Path is file:", stats.isFile());
    console.log("Path is directory:", stats.isDirectory());
  }
});

输出：

Stats object for: example_file.txt
Stats {
  dev: 3229478529,
  mode: 33206,
  nlink: 1,
  uid: 0,
  gid: 0,
  rdev: 0,
  blksize: 4096,
  ino: 281474976780635,
  size: 0,
  blocks: 0,
  atimeMs: 1584389463707.251,
  mtimeMs: 1582209885466.6848,
  ctimeMs: 1582209885466.6848,
  birthtimeMs: 1584389463707.251,
  atime: 2020-03-16T20:11:03.707Z,
  mtime: 2020-02-20T14:44:45.467Z,
  ctime: 2020-02-20T14:44:45.467Z,
  birthtime: 2020-03-16T20:11:03.707Z
}
Path is file: true
Path is directory: false
Stats object for: example_directory.txt
Stats {
  dev: 3229478529,
  mode: 16822,
  nlink: 1,
  uid: 0,
  gid: 0,
  rdev: 0,
  blksize: 4096,
  ino: 281474976780638,
  size: 0,
  blocks: 0,
  atimeMs: 1584429828080.8872,
  mtimeMs: 1581074249467.7114,
  ctimeMs: 1584389463715.2507,
  birthtimeMs: 1584389463715.2507,
  atime: 2020-03-17T07:23:48.081Z,
  mtime: 2020-02-07T11:17:29.468Z,
  ctime: 2020-03-16T20:11:03.715Z,
  birthtime: 2020-03-16T20:11:03.715Z
}
Path is file: false
Path is directory: true

示例 2：此示例使用 fs.fstat() 方法获取带有和不带有 bigint 选项的文件的详细信息。

// Node.js program to demonstrate the
// fs.fstat() method
  
// Import the filesystem module
const fs = require('fs');
  
// Define the file descriptor for a file
let file_fd = fs.openSync('example_file.txt', 'r');
  
fs.fstat(file_fd, (error, stats) => {
  console.log(stats);
});
  
// Using the bigint option to return
// the values in big integer format
fs.fstat(file_fd, { bigint: true }, (error, stats) => {
  console.log(stats);
});

输出：

Stats {
  dev: 3229478529,
  mode: 33206,
  nlink: 1,
  uid: 0,
  gid: 0,
  rdev: 0,
  blksize: 4096,
  ino: 281474976780635,
  size: 0,
  blocks: 0,
  atimeMs: 1584389463707.251,
  mtimeMs: 1582209885466.6848,
  ctimeMs: 1582209885466.6848,
  birthtimeMs: 1584389463707.251,
  atime: 2020-03-16T20:11:03.707Z,
  mtime: 2020-02-20T14:44:45.467Z,
  ctime: 2020-02-20T14:44:45.467Z,
  birthtime: 2020-03-16T20:11:03.707Z
}
BigIntStats {
  dev: 3229478529n,
  mode: 33206n,
  nlink: 1n,
  uid: 0n,
  gid: 0n,
  rdev: 0n,
  blksize: 4096n,
  ino: 281474976780635n,
  size: 0n,
  blocks: 0n,
  atimeMs: 1584389463707n,
  mtimeMs: 1582209885466n,
  ctimeMs: 1582209885466n,
  birthtimeMs: 1584389463707n,
  atimeNs: 1584389463707251000n,
  mtimeNs: 1582209885466684900n,
  ctimeNs: 1582209885466684900n,
  birthtimeNs: 1584389463707251000n,
  atime: 2020-03-16T20:11:03.707Z,
  mtime: 2020-02-20T14:44:45.466Z,
  ctime: 2020-02-20T14:44:45.466Z,
  birthtime: 2020-03-16T20:11:03.707Z
}

参考： https://nodejs.org/api/fs.html#fs_fs_fstat_fd_options_callback