Basic oc file read/write and operations, oc file read/write operations

Basic oc file read/write and operations, oc file read/write operations

Code:

# Import <Foundation/Foundation. h> // NSString Write File void stringWriteToFile () {NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "/Documents/test.txt"]; NSString * s = @ "test "; [s writeToFile: path atomically: YES encoding: NSUTF8StringEncoding error: nil]; NSString * str = [[NSString alloc] handler: path encoding: NSUTF8StringEncoding error: nil]; NSLog (@ "\ nstring = % @", str); NSS Tring * testtxt = [[NSString alloc] initWithContentsOfFile: path encoding: NSUTF8StringEncoding error: nil]; NSLog (@ "\ ntest. text = % @ ", testtxt);} // NSArray Write File void arrayWriteToFile () {NSArray * arr = @ [@" a ", @" B ", @ "B", @ "c"]; NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "/Documents/test2.txt"]; [arr writeToFile: path atomically: YES]; NSArray * a = [NSArray alloc] initWithContentsOfFi Le: path]; NSLog (@ "array = \ n % @", a); NSString * s = [[NSString alloc] initWithContentsOfFile: path encoding: NSUTF8StringEncoding error: nil]; NSLog (@ "\ ntest2.txt = \ n % @", s);} // NSDictionary Write File void dictionaryWriteToFile () {NSDictionary * dic ={ @ "": @ "1", @ "B": @ "2", @ "c": @ "3", @ "d": @ "4 "}; NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "/Documents/test3.txt"]; [dic writeToFile: path Atomically: YES]; NSDictionary * d = [[NSDictionary alloc] initWithContentsOfFile: path]; NSLog (@ "\ ndictionary = \ n % @", d ); NSString * s = [[NSString alloc] initWithContentsOfFile: path encoding: NSUTF8StringEncoding error: nil]; NSLog (@ "\ ntest3.txt = \ n % @", s );} // whether atomically writes data at the atomic level, that is, transactional data. // NSNumber, NSDate, and NSData can all write data to a file through writeToFile, which is of the plain text type, if you change the suffix to plist, The xcode attribute list file int main (int argc, const char * argv []) {// This method creates an instance, but the NSFileManager Singleton mode will be ineffective. NSFileManager * fm0 = [[NSFileManager alloc] init]; // defaultManager creates the NSFileManager object NSFileManager * fm1 = [NSFileManager defaultManager] in singleton mode; NSFileManager * fm2 = [NSFileManager defaultManager]; NSLog (@ "\ nfm0 = % p, fm1 = % p, fm2 = % p ", fm0, fm1, fm2); NSData * data = [[NSString stringWithFormat: @" main "] dataUsingEncoding: NSUTF8StringEncoding]; NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "events/main.txt"]; if (! [Fm1 fileExistsAtPath: path]) {if ([fm1 createFileAtPath: path contents: data attributes: nil]) {NSLog (@ "create success "); NSDictionary * d = [fm1 attributesOfItemAtPath: path error: nil]; NSLog (@ "\ nattributesOfItemAtPath = \ n % @", d ); // NSFileSize is the predefined File Attribute key. You can view the system file to obtain other attribute keys and obtain the attribute NSNumber * filesize = [d valueForKey: NSFileSize] using the following methods: NSLog (@ "\ nfilesize = % @", filesize); // read the file NSData * data1 = [fm1 contentsAtPath: path]; NSString * s = [[NSString alloc] initWithData: data1 encoding: NSUTF8StringEncoding]; // attributes of the file system // total space, used space, available space, number of files, NSLog (@ "\ nattributesOfFileSystemForPath = \ n % @", [fm1 attributesOfFileSystemForPath: path error: nil]); NSLog (@ "\ nmain.txt =%@", s) ;}} else {NSString * copypath = [NSHomeDirectory () stringByAppendingPathComponent: @ "/Documents/main_copy.txt"]; [fm1 copyItemAtPath: path toPath: copypath error: nil]; // rename: The target path is the same as the main path, but the file name is different. NSString * movepath = [NSHomeDirectory () stringByAppendingPathComponent: @ "/Documents/main_move.txt"]; [fm1 moveItemAtPath: path: movepath error: nil]; // Delete the object if ([fm1 removeItemAtPath: path error: nil]) {NSLog (@ "remove % @ success", path );} if ([fm1 removeItemAtPath: copypath error: nil]) {NSLog (@ "remove % @ success", copypath);} if ([fm1 removeItemAtPath: movepath error: nil]) {NSLog (@ "remove % @ success", movepath) ;}} stringWriteToFile (); arrayWriteToFile (); dictionaryWriteToFile (); return 0 ;}

Result:

2015-03-08 21:18:26.064 NSFileManagerDemo[1686:79942] fm0 = 0x1001145d0,fm1 = 0x100114620,fm2 = 0x1001146202015-03-08 21:18:26.075 NSFileManagerDemo[1686:79942] remove /Users/yoran_yang/Documents/main_copy.txt success2015-03-08 21:18:26.076 NSFileManagerDemo[1686:79942] remove /Users/yoran_yang/Documents/main_move.txt success2015-03-08 21:18:26.076 NSFileManagerDemo[1686:79942] string = test2015-03-08 21:18:26.077 NSFileManagerDemo[1686:79942] test.text = test2015-03-08 21:18:26.078 NSFileManagerDemo[1686:79942] array = (    a,    b,    b,    c)2015-03-08 21:18:26.078 NSFileManagerDemo[1686:79942] test2.txt = <?xml version="1.0" encoding="UTF-8"?><!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><array>    <string>a</string>    <string>b</string>    <string>b</string>    <string>c</string></array></plist>2015-03-08 21:18:26.079 NSFileManagerDemo[1686:79942] dictionary = {    a = 1;    b = 2;    c = 3;    d = 4;}2015-03-08 21:18:26.079 NSFileManagerDemo[1686:79942] test3.txt = <?xml version="1.0" encoding="UTF-8"?><!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><dict>    <key>a</key>    <string>1</string>    <key>b</key>    <string>2</string>    <key>c</key>    <string>3</string>    <key>d</key>    <string>4</string></dict></plist>Program ended with exit code: 0