在请求服务器时，如果参数中带有中文字符。就会报参数格式错误，需要将其转换成UTF8
@interface NSString (NSURLUtilities)
/* Adds all percent escapes necessary to convert the receiver into a legal URL string. Uses the given encoding to determine the correct percent escapes (returning nil if the given encoding cannot encode a particular character). See CFURLCreateStringByAddingPercentEscapes in CFURL.h for more complex transformations
*/
- (NSString *)stringByAddingPercentEscapesUsingEncoding:(NSStringEncoding)enc;
/* 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 *)stringByReplacingPercentEscapesUsingEncoding:(NSStringEncoding)enc;
@end
代码如下：
@"keyword": [searchSoft.text stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],