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nodeJS之路径PATH模块详解

前面的话 path模块包含一系列处理和转换文件路径的工具集,通过 require(‘path‘) 可用来访问这个模块。本文将详细介绍path模块 路径...

前面的话

path模块包含一系列处理和转换文件路径的工具集,通过 require(‘path‘) 可用来访问这个模块。本文将详细介绍path模块

路径组成

【path.dirname(p)】

返回路径p所在的目录

var path = require(‘path‘);
console.log(path.dirname(‘/foo/bar/baz/asdf/a.txt‘)); // /foo/bar/baz/asdf
console.log(path.dirname(‘/foo/bar/baz/asdf/‘)); // /foo/bar/baz
console.log(path.dirname(‘C:/test/aaa‘)); // C:/test

【path.basename(p[, ext])】

返回路径的最后一个部分,即文件名。参数ext为需要截掉的后缀内容 

var path = require(‘path‘);
console.log(path.basename(‘/foo/bar/baz/asdf/a.txt‘)); // a.txt
console.log(path.basename(‘/foo/bar/baz/asdf/a.txt‘,‘.txt‘)); // a
console.log(path.basename(‘/foo/bar/baz/asdf/‘)); // asdf
console.log(path.basename(‘C:/test/aaa‘)); // aaa

【path.extname(p)】

返回路径p的扩展名,从最后一个‘.‘到字符串的末尾。如果最后一个部分没有‘.‘,或者路径是以‘.‘开头,则返回空字符串

var path = require(‘path‘);
console.log(path.extname(‘/foo/bar/baz/asdf/a.txt‘)); // .txt
console.log(path.extname(‘/foo/bar/baz/asdf/a.txt.b‘)); // .b
console.log(path.extname(‘/foo/bar/baz/asdf/a.‘)); // .
console.log(path.extname(‘C:/test/aaa/.‘)); // ‘‘
console.log(path.extname(‘C:/test/aaa‘)); // ‘‘

分隔符

【path.sep】

返回对应平台下的文件分隔符,win下为‘‘,*nix下为‘/‘

var path = require(‘path‘);
console.log(path.sep); // win下为,*nix下为/
console.log(‘foo\bar\baz‘.split(path.sep)); // [ ‘foo‘, ‘bar‘, ‘baz‘ ]
console.log(‘foo/bar/baz‘.split(path.sep)); // win下返回[‘foo/bar/baz‘],但在*nix系统下会返回[‘foo‘,‘bar‘,‘baz‘]

【path.delimiter】

返回对应平台下的路径分隔符,win下为‘;‘,*nix下为‘:‘

var path = require(‘path‘);
console.log(path.delimiter); //win下为“;”,*nix下为“:”
console.log(path.sep); // win下为,*nix下为/

规范化

【path.normalize(p)】

规范化路径,处理冗余的“..”、“.”、“/”字符。发现多个斜杠时,会替换成一个斜杠。当路径末尾包含一个斜杠时,保留。Windows系统使用反斜杠 

var path = require(‘path‘);
console.log(path.normalize(‘a/b/c/../user/bin‘));//auserin
console.log(path.normalize(‘a/b/c///../user/bin/‘));//auserin
console.log(path.normalize(‘a/b/c/../../user/bin‘));//auserin
console.log(path.normalize(‘a/b/c/.././///../user/bin/..‘));//auser
console.log(path.normalize(‘a/b/c/../../user/bin/../../‘));//a
console.log(path.normalize(‘a/../../user/bin/../../‘));//..
console.log(path.normalize(‘a/../../user/bin/../../../../‘));//......
console.log(path.normalize(‘./a/.././user/bin/./‘));//userin

【path.join([path1], [path2], [...])】

将多个路径结合在一起,并转换为规范化路径 

var path = require(‘path‘);
console.log(path.join(‘////./a‘, ‘b////c‘, ‘user/‘));//acuser
console.log(path.join(‘a‘, ‘../../‘, ‘user/‘));//..user

绝对和相对

【path.resolve([from ...], to)】

从源地址 from 到目的地址 to 的绝对路径,类似在shell里执行一系列的cd命令

path.resolve(‘foo/bar‘, ‘/tmp/file/‘, ‘..‘, ‘a/../subfile‘)

类似于:

cd foo/bar
cd /tmp/file/
cd ..
cd a/../subfile
pwd

[注意]如果某个from或to参数是绝对路径(比如 ‘E:/abc‘,或是以“/”开头的路径),则将忽略之前的from参数

var path = require(‘path‘);
console.log(path.resolve(‘.‘, ‘testFiles/..‘, ‘trdLayer‘));//D:project	rdLayer
console.log(path.resolve(‘..‘, ‘testFiles‘, ‘a.txt‘));//D:	estFilesa.txt
console.log(path.resolve(‘D:‘, ‘abc‘, ‘D:/a‘));//D:a
console.log(path.resolve(‘abc‘, ‘ok.gif‘));//D:projectabcok.gif
console.log(path.resolve(‘abc‘, ‘..‘, ‘a/../subfile‘)); //D:projectsubfile

【path.isAbsolute(path)】

path是一个绝对路径(比如 ‘E:/abc‘),或者是以“/”开头的路径,二者都会返回true

var path = require(‘path‘);
console.log(path.isAbsolute(‘../testFiles/secLayer‘));//false
console.log(path.isAbsolute(‘./join.js‘));//false
console.log(path.isAbsolute(‘temp‘));//false
console.log(path.isAbsolute(‘/temp/../..‘));//true
console.log(path.isAbsolute(‘E:/github/nodeAPI/abc/efg‘));//true
console.log(path.isAbsolute(‘///temp123‘));//true

【path.relative(from, to)】

获取从 from 到 to 的相对路径,可以看作 path.resolve 的相反实现

path.resolve(from, path.relative(from, to)) == path.resolve(to)

var path = require(‘path‘);
console.log(path.relative(‘C:\	est‘, ‘C:\impl\bbb‘));//..implbb
console.log(path.relative(‘C:/test/aaa‘, ‘C:/bbb‘));//....bb
console.log(path.relative(‘C:/test/aaa‘, ‘D:/bbb‘));//D:bb