原文地址：http://blog.csdn.net/huifeidexin_1/article/details/7883984
iOS中编码转化
1.UTF-8转化
NSString *data = @"你好，北京！";
//转换成UTF-8
NSString *dataUTF8 = [datastringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@",dataUTF8);
//UTF-8转GBK,将UTF8代码替换，官方解释如下。
//Replaces all percent escapes with the matching characters as determined by the given encoding. Returns nil if the transformation is not possible (i.e. the percent escapes give a byte sequence not legal in the given encoding). See CFURLCreateStringByReplacingPercentEscapes in CFURL.h for more complex transformations
NSString *dataGBK = [dataUTF8stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@",dataGBK);
在Xcode4.2中执行结果如下：
将上述方法封装，如下：
//Unicode转UTF-8
+ (NSString *)encodeToPercentEscapeString: (NSString *) input
{
// Encode all the reserved characters, per RFC 3986
// (<http://www.ietf.org/rfc/rfc3986.txt>)
NSString *outputStr = (NSString *)
CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
(CFStringRef)input,
NULL,
(CFStringRef)@"!*‘();:@&=+$,/?%#[]",
kCFStringEncodingUTF8);
return outputStr;
}
+ (NSString *)decodeFromPercentEscapeString: (NSString *) input
{
NSMutableString *outputStr = [NSMutableStringstringWithString:input];
[outputStr replaceOccurrencesOfString:@"+"
withString:@" "
options:NSLiteralSearch
range:NSMakeRange(0, [outputStrlength])];
return [outputStrstringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}
2.UTF-8和Unicode转化
//Unicode转UTF-8
+ (NSString*) replaceUnicode:(NSString*)aUnicodeString
{
NSString *tempStr1 = [aUnicodeStringstringByReplacingOccurrencesOfString:@"\\u"withString:@"\\U"];
NSString *tempStr2 = [tempStr1stringByReplacingOccurrencesOfString:@"\""withString:@"\\\""];
NSString *tempStr3 = [[@"\""stringByAppendingString:tempStr2] stringByAppendingString:@"\""];
NSData *tempData = [tempStr3dataUsingEncoding:NSUTF8StringEncoding];
NSString* returnStr = [NSPropertyListSerializationpropertyListFromData:tempData
mutabilityOption:NSPropertyListImmutable
format:NULL
errorDescription:NULL];
return [returnStrstringByReplacingOccurrencesOfString:@"\\r\\n"withString:@"\n"];
}
+(NSString *) utf8ToUnicode:(NSString *)string
{
NSUInteger length = [string length];
NSMutableString *s = [NSMutableStringstringWithCapacity:0];
for (int i = 0;i < length; i++)
{
unichar _char = [string characterAtIndex:i];
//判断是否为英文和数字
if (_char <= ‘9‘ && _char >=‘0‘)
{
[s appendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];
}
else if(_char >=‘a‘ && _char <= ‘z‘)
{
[s appendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];
}
else if(_char >=‘A‘ && _char <= ‘Z‘)
{
[s appendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];
}
else
{
[s appendFormat:@"\\u%x",[stringcharacterAtIndex:i]];
}
}
return s;
}