Introduction to File read classes (Nsfilehandle) in OC and common usage methods

Nsfilehandle

Nsfilemanager class mainly for file operation (delete, modify, move, assign value, etc.)

// to determine if there is a tagetpath file path, create no

nsfilemanager *filemanage = [nsfilemanager defaultmanager];

BOOL success = [Filemanage createfileatpath: Tagetpath contents:nil attributes :nil];

if (success) {

NSLog(@ "Create success");

}

The Nsfilehandle class primarily reads and writes the contents of a file

Nsfilehandle steps to process a file

1: Create a Nsfilehandle object

// Create flow

nsfilehandle *infilehandle = [nsfilehandle filehandleforreadingatpath: Srcpath];

nsfilehandle *outfilehandle = [nsfilehandle filehandleforwritingatpath: Tagetpath];

2: I/O operations on open files

//Get file path

nsstring *homepath = nshomedirectory();

nsstring *filepath = [HomePath stringbyappendingpathcomponent:@ "Phone/date.text"];

Nsfilehandle *filehandle = [nsfilehandle filehandleforupdatingatpath: FilePath];

　Navigate to the last

[filehandle seektoendoffile];

//Navigate to a location, after 100 bytes

[FileHandle seektofileoffset:];

// Append Data

nsstring *str = @ "Add World";

nsdata *stringdata = [str datausingencoding:nsutf8stringencoding];

// Append write Data

[FileHandle writedata: stringdata];

3: Close File object operation

　Close the stream
[FileHandle closefile];

Common processing methods, reading

Read File contents

void Readbyfile () {

// file path

nsstring *homepath = nshomedirectory();

nsstring *filepath = [HomePath stringbyappendingpathcomponent:@ "Phone/cellphone.text" ];     

nsfilehandle *filehandle = [nsfilehandle filehandleforreadingatpath: FilePath];

nsinteger length = [filehandle availabledata]. Length;

// jump to the specified location

[FileHandle seektofileoffset: length/2];

nsdata *data = [FileHandle readdatatoendoffile];

nsstring *str = [[nsstring alloc] initwithdata:d ata encoding: Nsutf8stringencoding];

NSLog(@ "%@", str);

[FileHandle closefile];

}

Copying Files

void Copy2other () {

nsstring *homepath = nshomedirectory();

nsstring *filepath = [HomePath stringbyappendingpathcomponent:@ "Phone/cellphone.text"];

nsstring *tagetpath = [HomePath stringbyappendingpathcomponent:@ "Phone/cellphone_bak.text" ];

// Do you have this file, no then create

nsfilemanager *filemanage =[nsfilemanager defaultmanager];

BOOL success = [Filemanage createfileatpath: Tagetpath contents:nil attributes :nil];

if (success) {

NSLog(@ "Create success");

}

// Read the source file via Nsfilehandle , write to another file

nsfilehandle *outfilehandle = [nsfilehandle filehandleforwritingatpath: Tagetpath];

nsfilehandle *infilehandle = [nsfilehandle filehandleforreadingatpath: FilePath];

nsdata *data = [Infilehandle readdatatoendoffile];

[Outfilehandle writedata:d ATA];

// close stream

[Infilehandle closefile];

[Outfilehandle closefile];

}

Introduction to File read classes (Nsfilehandle) in OC and common usage methods