nsstring转换---ios

1. NSString转化为UNICODE String：

(NSString*)fname ＝ @“Test”;

char fnameStr[10];

memcpy(fnameStr, [fname cStringUsingEncoding:NSUnicodeStringEncoding], 2*([fname length]));

与strcpy相比，memcpy并不是遇到'\0'就结束，而是一定会拷贝完n个字节

2. NSString 转化为 char *

NSString * str＝ @“Test”;

const char * a =[str UTF8String];

3.char * 转化为 NSString

NSString *str=[NSString stringWithCString  encoding:NSUTF8StringEncoding];

4. char * 转化 NSData

方法一：

char * a = (char*)malloc(sizeof(byte)*16);

NSData *data = [NSData dataWithBytes: a  length:strlen(a)];

方法二：

转换为NSString： - (id)initWithUTF8String:(const char *)bytes

然后用NSString的 - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding

5. NSData 转化 char *

NSData data ；

char* a=[data bytes];

6. NSData 转化 NSString;

NSData* data;

NSString* aStr= ［NSString alloc] initWithData:data  encoding:NSASCIIStringEncoding];

7. NSString 转化 NSData对象

NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];

NSString 转化 NSURL

//NSURL *url = [NSURL URLWithString:[str  stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding ]];

NSString *urlString=[@"http://www.google.com/search?client=safari&rls=en&q=搜索&ie=UTF-8&oe=UTF-8" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSString 转化 NSURL

//NSURL *url = [NSURL URLWithString:[str  stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding ]];

NSString *urlString=[@"http://www.google.com/search?client=safari&rls=en&q=搜索&ie=UTF-8&oe=UTF-8" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSURL 转化 NSString

NSURL *url=[NSURL URLWithString:urlString];

NSString *s=[[url absoluteString] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];