Some chars changed in NSString

问题:

I'm retrieving a string from url content, this way:

NSString *urlStr = [NSString stringWithFormat:@"http://www.example.com/string_to_retrieve"];
NSURL *url = [NSURL URLWithString:urlStr];
NSString *resp = [NSString stringWithContentsOfURL:url encoding:NSASCIIStringEncoding error:nil];

and writing it to file, this way:

NSString *outFile = @"/path/to/myfile";
[resp writeToFile:outFile atomically:YES encoding:NSUTF8StringEncoding error:nil];

my string contains several special chars like "ö" which should be represented by "F6" hex value, but when i try to open with a hex editor the file where my string is written, i see that "ö" (F6) got converted to two other chars: "ö" (C3 B6)

I tried with several other string encodings in both

NSString *resp = [NSString stringWithContentsOfURL:url encoding:NSASCIIStringEncoding error:nil];

and

[resp writeToFile:outFile atomically:YES encoding:NSUTF8StringEncoding error:nil];

but always with bad results...

NSASCIIStringEncoding seems to be the only way that i can get that string from my url: if i use other encodings like NSUTF8StringEncoding all i get is nil

NSUTF8StringEncoding seems to be the only way i can write to my file: if i use other encodings like NSASCIIStringEncoding all i get is a 0 byte file

So how can i properly retrieve and write that string to my file?

回答1:

F6 is the character code of "ö" in the NSISOLatin1StringEncoding, so

[resp writeToFile:outFile atomically:YES encoding:NSISOLatin1StringEncoding error:nil];

should give the desired result. (NSISOLatin2StringEncoding works as well. I am not sure about the differences. The documentation of the supported encodings is not very verbose.)

---

Update:

• NSISOLatin1StringEncoding is the ISO-8859-1 encoding, which is intended for "Western European" languages.
• NSISOLatin2StringEncoding is the ISO-8859-2 encoding, which is intended for "Eastern European" languages.
• @Esailija states (see comments below) that Windows-1252 might be a better choice, the corresponding encoding is NSWindowsCP1252StringEncoding.