Read and write files
Nodejs in the operation is relatively simple and much! Let's take a look at some examples.
"Write Text File"
Wfile.js
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The code is as follows |
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var fs = require ("FS");
var data = ' Hello Rainforest blog '; Fs.writefile (' C:a.txt ', data, ' ASCII ', function (err) { if (err) { Console.log (' Write file failed '); }else{ Console.log (' Save success, hurry to see garbled '); } }) |
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[Note: By default, the data is encoded as utf8;mode=438; Flag=w]
"Read text file"
Rfile.js
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The code is as follows |
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var fs = require ("FS");
var data = ' Hello Rainforest blog '; Fs.readfile (' c:a.txt ', ' ASCII ', function (err, data) { if (err) { Console.log (' Write file failed '); }else{ Console.log (data); } })
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[Note: If there is no special encoding, then the binary buffered data is returned.] ]
[Note: Binary buffered data printing results: <buffer 6c 6c 6f E8 A2>]
File directory Operations
Nodejs file operation (FS)
When manipulating files, we need to require (load) the file System package to obtain the document operation function.
The code is as follows |
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var fs = require ("FS"); |
And this fs how to use it, this time we need to query Nodejs official API
Http://nodejs.org/api/fs.html
Basic file operations include: New, rename, delete, and so on, to see a few examples
"New Folder"
The code is as follows |
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Newfolder.js ----------------------------- Load File System module var fs = require ("FS");
Create a folder named A on the C disk Fs.mkdir ("C:a", function (Err) { if (!err) { Console.log ("Operation successful!") "); }else{ Console.log (The operation failed!) "); } }); |
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[Note: If the folder exists err, there will be an error message.] ]
"Delete Folder"
The code is as follows |
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Removefolder.js ----------------------------- var fs = require ("FS");
Delete Folder A in C disk Fs.rmdir ("C:a", function (Err) { if (err) { Console.log (delete failed!) "); }else{ Console.log ("Delete succeeded!") "); } }); |
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[Note: If the delete folder does not exist, err will have an error message.] ]
"Rename Folder"
Rename.js
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The code is as follows |
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var fs = require ("FS");
Rename Folder A to B Fs.rename ("C:a", "c:b", function (Err) { if (err) { Console.log (rename failed!) "); }else{ Console.log ("Rename succeeded!") "); } }); |
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[Note: The folder does not exist, so err has an error message.] ]
"Determine if a file/folder exists"
The code is as follows |
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Exsits.js ----------------------------- var fs = require ("FS");
Determine if a folder exists Fs.exists ("C:a", function (exists) { if (exists) { Console.log ("A folder exists"); }else{ Console.log ("folder A does not exist") } }); |
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[Note: Then call the ' callback argument with either True or false
(This callback function parameter value is TRUE or false)]
"Judge file Type" [Fs.stat (), Fs.lstat () and Fs.fstat ()]
Stat.js
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The code is as follows |
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var fs = require ("FS");
Get the type of folder a Fs.stat ("C:a", Function (err, stat) { if (err) { Console.log ("file does not exist!") "); }else{ Console.log ("Whether file:" +stat.isfile ()); Console.log ("Whether folder:" +stat.isdirectory ()); } }); |
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[
Other State functions:
Stats.isfile ()
Stats.isdirectory ()
Stats.isblockdevice ()
Stats.ischaracterdevice ()
Stats.issymboliclink () (only valid for Fs.lstat ())
Stats.isfifo ()
Stats.issocket ()]