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NSString / NSData / char* 类型之间的转换

NSString / NSData / char* 类型之间的转换

 

转自:http://www.cnblogs.com/pengyingh/articles/2341880.html

 

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 = http://www.mamicode.com/[NSData dataWithBytes: a   length:strlen(a)];>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 = http://www.mamicode.com/[@"testdata" dataUsingEncoding:NSUTF8StringEncoding];http://blog.sina.com.cn/s/articlelist_1256141290_14_1.html
 
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:0] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding ]]; 
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; 
[request setHTTPMethod:@"POST"]; 

NSMutableArray *_array = [[NSMutableArray alloc] initWithCapacity:0]; 
for (int i = 1; i < [arr count]; ++i ){ 
NSString *str = [arr objectAtIndex:i]; 
[_array addObject:str]; 

[_array componentsJoinedByString:@"&"]; 
NSData *data = http://www.mamicode.com/[[_array componentsJoinedByString:@"&"] dataUsingEncoding: NSASCIIStringEncoding]; 
[request setHTTPBody:data];
 // 发送请求并获得服务器反馈的数据
    NSData *urldata = http://www.mamicode.com/[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 = http://www.mamicode.com/[NSData dataWithContentsOfURL:url];
3 NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
4 NSString *retStr = [[NSString alloc] initWithData:data encoding:enc];

NSString / NSData / char* 类型之间的转换