UNICODE编码转表情

 NSString *emojiEscaped = @"\\ud83c\\udf81";

- (NSString*)decode:(NSString*)string{
    NSData *emojiData = [string dataUsingEncoding:NSUTF8StringEncoding];
    NSString *emojiString = [[NSString alloc] initWithData:emojiData encoding:NSNonLossyASCIIStringEncoding];
    return emojiString;
}

- (NSString*)encode:(NSString*)string{
    NSString *uniStr = [NSString stringWithUTF8String:[string UTF8String]];
    NSData *uniData = [uniStr dataUsingEncoding:NSNonLossyASCIIStringEncoding];
    NSString *goodStr = [[NSString alloc] initWithData:uniData encoding:NSUTF8StringEncoding] ;
    NSLog(@"---编码--->[%@]",goodStr);
    return goodStr;
}