+(NSString*)encodeString:(NSString*)unencodedString{
    
    // CharactersToBeEscaped = @":/?&=;+!@#$()~',*";
    
    // CharactersToLeaveUnescaped = @"[].";
    
    NSString*encodedString=(NSString*)
    
    CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                              
                                                              (CFStringRef)unencodedString,
                                                              
                                                              NULL,
                                                              
                                                              (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                              
                                                              kCFStringEncodingUTF8));
    
    return encodedString;
    
}

//URLDEcode
//解码
-(NSString*)decodeString:(NSString*)encodedString

{
    
    //NSString *decodedString = [encodedString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding ];
    
    NSString*decodedString=(__bridge_transfer NSString*)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(NULL,
                                                                                                               
                                                                                                               (__bridge CFStringRef)encodedString,
                                                                                                               
                                                                                                               CFSTR(""),
                                                                                                               
                                                                                                               CFStringConvertNSStringEncodingToEncoding(NSUTF8StringEncoding));
    
    return decodedString;
    
}