iphone里读取gb2312.doc

iphone里读取gb2312（中文）编码文件或者二进制流。说到文字编码，与文件读写打过交道的软件开发人员应该都知道，比如国际通用：UTF-8编码，ANSCII编码，Unicode编码中文：GB2312，GBK日文，Shiftjis等等。说了这么多无关紧要的话，技术是来解决实际问题的：1。如何读取UTF-8编码的文本文件？2。如何读取GB2312（中文）的文本文件？3。如何读取其它编码文件？首先解决第一个问题，1。如何读取UTF-8编码的文本文件？ NSString *filePath = NSBundle mainBundle bundlePath stringByAppendingPathComponent:fileName; NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil /当然也可以采用如下方法 /NSData *data = NSData dataWithContentsOfFile:filePath; /NSString *textFile = NSString alloc initWithData:data encoding:NSUTF8StringEncoding;2。如何读取GB2312（中文）的文本文件？可能很多人会想到，那还不简单，apple肯定提供了gb2312的文件编码常量，让我们看看有那些常量吧，看看 NSUTF8StringEncoding定义文件，应该会有GB2312的常量定义。/* Note that in addition to the values explicitly listed below, NSStringEncoding supports encodings provided by CFString.See CFStringEncodingExt.h for a list of these encodings.See CFString.h for functions which convert between NSStringEncoding and CFStringEncoding.*/enum NSASCIIStringEncoding = 1,/* 0.127 only */ NSNEXTSTEPStringEncoding = 2, NSJapaneseEUCStringEncoding = 3, NSUTF8StringEncoding = 4, NSISOLatin1StringEncoding = 5, NSSymbolStringEncoding = 6, NSNonLossyASCIIStringEncoding = 7, NSShiftJISStringEncoding = 8, /* kCFStringEncodingDOSJapanese */ NSISOLatin2StringEncoding = 9, NSUnicodeStringEncoding = 10, NSWindowsCP1251StringEncoding = 11, /* Cyrillic; same as AdobeStandardCyrillic */ NSWindowsCP1252StringEncoding = 12, /* WinLatin1 */ NSWindowsCP1253StringEncoding = 13, /* Greek */ NSWindowsCP1254StringEncoding = 14, /* Turkish */ NSWindowsCP1250StringEncoding = 15, /* WinLatin2 */ NSISO2022JPStringEncoding = 21, /* ISO 2022 Japanese encoding for e-mail */ NSMacOSRomanStringEncoding = 30, NSUTF16StringEncoding = NSUnicodeStringEncoding, /* An alias for NSUnicodeStringEncoding */#if MAC_OS_X_VERSION_10_4 = MAC_OS_X_VERSION_MAX_ALLOWED | _IPHONE_2_0 = _IPHONE_OS_VERSION_MAX_ALLOWED NSUTF16BigEndianStringEncoding = 0x90000100, /* NSUTF16StringEncoding encoding with explicit endianness specified */ NSUTF16LittleEndianStringEncoding = 0x94000100, /* NSUTF16StringEncoding encoding with explicit endianness specified */ NSUTF32StringEncoding = 0x8c000100, NSUTF32BigEndianStringEncoding = 0x98000100, /* NSUTF32StringEncoding encoding with explicit endianness specified */ NSUTF32LittleEndianStringEncoding = 0x9c000100 /* NSUTF32StringEncoding encoding with explicit endianness specified */#endif;很遗憾，我没找到，不过Apple留了个线索让我取找，不过仔细看看它的注释 Note that in addition to the values explicitly listed below, NSStringEncoding supports encodings provided by CFString.See CFStringEncodingExt.h for a list of these encodings. See CFString.h for functions which convert between NSStringEncoding and CFStringEncoding. 我的英文比较不好，但大意是看明白了，不在下面支持了编码格式，在CFStringEncodingExt.h 里头文件申明 。我们通过finder的文件查找方法找到CFStringEncodingExt.h 。仔细看看确实找到了kCFStringEncodingGB_18030_2000 ( 我以为是kCFStringEncodingGB_2312_80 ,实际上不是) 但是这个是CFStringEncoding类型,我们需要NSEncode的类型。CFString 和NSString具有相同的内存结构，也是NSString的重要补充，通过查找CFString的帮助文档，找到了这个方法 CFStringConvertEncodingToNSStringEncoding NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000); NSString *textFile = NSString stringW