Nsfilehandle, Nsfilemange

The use of Nsfilehandle has been not proficient, inadvertently found the detailed introduction, showings convenient usage

Nsfilehandle This class is primarily read and write to the file contents

Nsfilemange This class is primarily the operation of files and the acquisition of file information

Common processing methods

+ (ID) Filehandleforreadingatpath: (NSString *) path opens a file ready to read

+ (ID) Filehandleforwritingatpath: (NSString *) path opens a file ready to write

+ (ID) Filehandleforupdatingatpath: (NSString *) path opens a file ready for update

-(NSData *) Availabledata; Returning available data from a device or channel

-(NSData *) readdatatoendoffile; Reads from the current node to the end of the file

-(NSData *) Readdataoflength: (nsuinteger) length; Reads the specified length data starting from the current node

-(void) WriteData: (NSData *) data; Write Data

-(unsigned long long) offsetinfile; Gets the offset of the current file

-(void) Seektofileoffset: (unsigned long long) offset; Jumps to the offset of the specified file

-(unsigned long long) seektoendoffile; Jump to end of file

-(void) Truncatefileatoffset: (unsigned long long) offset; Set the length of the file to offset bytes

-(void) closefile; Close File

Append data to a file

NSString *homepath = Nshomedirectory ();         

NSString *sourcepath = [HomePath stringbyappendingpathconmpone:@ "Testfile.text"];

Nsfilehandle *fielhandle = [Nsfilehandle Filehandleforupdatingatpath:sourcepath];

[FileHandle Seektoendoffile]; To jump a node to the end of a file

NSString *str = @ "Append data"

nsdata* stringdata = [str datausingencoding:nsutf8stringencoding];

[FileHandle Writedata:stringdata]; Append Write Data

[FileHandle CloseFile];

Locating data

Nsfilemanager *FM = [Nsfilemanager Defaultmanager];

NSString *content = @ "abcdef";

[FM Createfileatpath:path contents:[content datausingencoding:nsutf8stringencoding] attributes:nil];

Nsfilehandle *filehandle = [Nsfilehandle Filehandleforreadingatpath:path];

Nsuinteger length = [filehandle availabeldata] length]; Get Data length

[FileHandle SEEKTOFILEOFFSET;LENGTH/2]; Half of the offset file

NSData *data = [FileHandle readdatatoendoffile];

[FileHandle CloseFile];

Copying files

Nsfilehandle *infile, *outfile; Input file, output file

NSData *buffer; Buffered data read

Nsfilemanager *filemanager = [Nsfilemanager Defaultmanager];

NSString *homepath = Nshomedirectory ();

NSString *sourcepath = [HomePath stringbyappendingpathcomponent:@ "testfile.txt"]; Source file path

NSString *outpath = [HomePath stringbyappendingpathcomponent:@ "Outfile.txt"]; Output file path

BOOL sucess = [FileManager createfileatpath:outpath contents:nil Attributes:nil];

if (!success)

{

return N0;

}

infile = [Nsfilehandle Filehandleforreadingatpath:sourcepath]; Create read source Path file

if (infile = = nil)

{

return NO;

}

outfile = [Nsfilehandle Filehandleforreadingatpath:outpath]; Create a disease open file to output

if (outfile = = nil)

{

return NO;

}

[OutFile truncatefileatoffset:0]; Set the length of the output file to 0

Buffer = [infile readdatatoendoffile]; Reading data

[OutFile Writedata:buffer]; Write input

[InFile CloseFile]; Close write, input file

[OutFile CloseFile];

Nsfilehandle, Nsfilemange