iOS NSString和NSDate转换

NSDateFormatter
*dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter
setDateFormat:@

"yyyy-MM-dd HH:mm:ss"

];

NSString
*strDate = [dateFormatter stringFromDate:[NSDate date]];

----------------------------------------------------------------------

NSString转换成NSSdate：

[dateFormatter
setDateFormat:@

"yyyy-MM-dd HH:mm:ss"

];

NSDate
*date = [dateFormatter dateFromString:@

"2011-11-11 11:11:11"

];