iOS基本符号化フォーマット変換

iOS 

1.UTF-8 

    NSString *data = @" ， ！";

    // UTF-8

    NSString *dataUTF8 = [data stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSLog(@"%@",dataUTF8);

    //UTF-8 GBK, UTF8 ， 。

//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 = [dataUTF8 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSLog(@"%@",dataGBK);


 Xcode4.2 ：


 ， ：

//Unicode 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 = [NSMutableString stringWithString:input];  

    [outputStr replaceOccurrencesOfString:@"+"  

                               withString:@" "  

                                  options:NSLiteralSearch  

                                    range:NSMakeRange(0, [outputStr length])];  

    

    return [outputStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];  

}

2.UTF-8 Unicode 
//Unicode UTF-8

+ (NSString*) replaceUnicode:(NSString*)aUnicodeString

{

    NSString *tempStr1 = [aUnicodeString stringByReplacingOccurrencesOfString:@"\\u" withString:@"\\U"];  

    NSString *tempStr2 = [tempStr1 stringByReplacingOccurrencesOfString:@"\"" withString:@"\\\""];  

    NSString *tempStr3 = [[@"\"" stringByAppendingString:tempStr2] stringByAppendingString:@"\""];  

    NSData *tempData = [tempStr3 dataUsingEncoding:NSUTF8StringEncoding];  

    NSString* returnStr = [NSPropertyListSerialization propertyListFromData:tempData  

                                                           mutabilityOption:NSPropertyListImmutable   

                                                                     format:NULL  

                                                           errorDescription:NULL];  

    

    return [returnStr stringByReplacingOccurrencesOfString:@"\\r\
" withString:@"
"]; 

}



+(NSString *) utf8ToUnicode:(NSString *)string

{

    NSUInteger length = [string length];

    NSMutableString *s = [NSMutableString stringWithCapacity:0];

    for (int i = 0;i < length; i++) 

    {

        unichar _char = [string characterAtIndex:i];

        // 

        if (_char <= '9' && _char >= '0') 

        {

            [s appendFormat:@"%@",[string substringWithRange:NSMakeRange(i, 1)]];

        }

        else if(_char >= 'a' && _char <= 'z')

        {

            [s appendFormat:@"%@",[string substringWithRange:NSMakeRange(i, 1)]];

            

        }

        else if(_char >= 'A' && _char <= 'Z')

        {

            [s appendFormat:@"%@",[string substringWithRange:NSMakeRange(i, 1)]];

            

        }

        else

        {

            [s appendFormat:@"\\u%x",[string characterAtIndex:i]];

        }

    }

    return s;

}