NSString *str = @"www.baidu.com";
//将string转化URL
NSURL *url= [NSURL URLWithString:str];
//将URL转化string
NSString *string = [url absoluteString];
NSString *str = @"www.baidu.com";
//将string转化URL
NSURL *url= [NSURL URLWithString:str];
//将URL转化string
NSString *string = [url absoluteString];