NSString和NSDate对象之间的相互转换

NSString 转换成NSData 对象

[cpp] NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding]; 
NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];NSData 转换成NSString对象

[cpp] NSData * data;  
NSString *result = [[NSString alloc] initWithData:data  encoding:NSUTF8StringEncoding]; 
NSData * data;
NSString *result = [[NSString alloc] initWithData:data  encoding:NSUTF8StringEncoding];NSData 转换成char*

[cpp] NSData *data;  
char *test=[data bytes]; 
NSData *data;
char *test=[data bytes];char* 转换成NSData对象
[cpp] byte* tempData = malloc(sizeof(byte)*16);  
NSData *content=[NSData dataWithBytes:tempData length:16]; 
byte* tempData = malloc(sizeof(byte)*16);
NSData *content=[NSData dataWithBytes:tempData length:16];