从文件读取字符串和中文乱码解决

NSString *path = @"/User/desktop/text.txt";
//可解析中文
NSString *str = [NSString stringWithContentOfFile:path
                           encoding:NSUTF8StringEncoding error:nil];

//如果解析gbk中文，需要用encoding kFCStringEncodingGB_2312
//而且必须转类型，CFStringConvertNSStringEncodingToEncoding(encoding kFCStringEncodingGB_2312)

//url也可以远程访问网页
NSURL *url = [NSURL URLWithString: @"file///User/Desktop/text.txt"];
NSString *str = [NSString stringWithContentsOfURL: url 
                            encoding:NSUTF8StringEncoding error:nil];