1、定义一个NSCharacter(由于NSString中有全角符号和半角符号, 因此有些符号要包括全角和半角的)

NSCharacterSet *set=[NSCharacterSet characterSetWithCharactersInString:@"/@／：；（）¥「」/＂、[]{}#%-*+=_\\|~＜＞$€^•’@#$%^&*()_+’\""];

2、调用stringByTrimmingCharactersInSet

NSString*trimmedString=[string stringByTrimmingCharactersInSet:set];

3、去除两端的空格

NSString*temptext=[messageTextField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

4、去除两端的回车

NSString*text=[temptext stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];