NSString 转换成NSData 对象
NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];
NSData 转换成NSString对象
NSData * data; NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSData 转换成char*
NSData *data;
2 char *test=[data bytes];
char* 转换成NSData对象
byte* tempData = malloc(sizeof(byte)*);
2 NSData *content = [NSData dataWithBytes:tempData length:];
1. NSString转化为UNICODE String：
(NSString*)fname ＝ @“Test”;
char fnameStr[];
memcpy(fnameStr, [fname cStringUsingEncoding:NSUnicodeStringEncoding], *([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：
1 char * a = (char*)malloc(sizeof(byte)*); 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];
NSURL 转化 NSString
NSURL *url=[NSURL URLWithString:urlString];
NSString *s=[[url absoluteString] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSArray *arr = [urlStr componentsSeparatedByString:@"&"];
NSURL *url = [NSURL URLWithString:[[arr objectAtIndex:] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding ]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"]; NSMutableArray *_array = [[NSMutableArray alloc] initWithCapacity:];
for (int i = ; i < [arr count]; ++i ){
NSString *str = [arr objectAtIndex:i];
[_array addObject:str];
}
[_array componentsJoinedByString:@"&"];
NSData *data = [[_array componentsJoinedByString:@"&"] dataUsingEncoding: NSASCIIStringEncoding];
[request setHTTPBody:data];
// 发送请求并获得服务器反馈的数据
NSData *urldata = [AESEnCDeCViewController Get:url]; // 第一种 转换NSData数据到char*字符串
char * test = (char*)[urldata bytes];
std::string old = deaes(test); // 第二种 转换NSData到UTF8编码的NSString中再转换为char*字符串
// NSString *desStr = [[NSString alloc] initWithData:urldata encoding:NSUTF8StringEncoding];
// const char *desresult = [desStr UTF8String];
// std::string old = deaes(desresult); // 解密字字符串到明文
NSString *oldstr = [[NSString alloc] initWithCString:old.c_str()];
很多时候软件读取的中文网页编码集是gb2312，所以显示出来的是乱码。这时需要将NSString文字编码转换
1 NSURL *url = [NSURL URLWithString:urlStr];
2 NSData *data = [NSData dataWithContentsOfURL:url];
3 NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
4 NSString *retStr = [[NSString alloc] initWithData:data encoding:enc];