NSString 转换成NSData 对象
NSData* newData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];
NSData 转换成NSString对象
NSData * data;
NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
在iOS底层网络的开发中,会遇到NSData 转 NSString 为空的情况,原因很多,下面的解决方法是针对从服务器传过来的数据中含有非UTF-8字符(主要是UTF-8)的情况。
用libiconv清除非utf8字符
先给项目Link Binaries With Library 添加libiconv.dylib
使用如下函数对NSData进行清理,再进行转换就OK了
-(NSData *)cleanUTF8:(NSData *)data {
iconv_t cd = iconv_open("UTF-8", "UTF-8"); // 从utf8转utf8
int one = 1;
iconvctl(cd, ICONV_SET_DISCARD_ILSEQ, &one); // 丢弃不正确的字符
size_t inbytesleft, outbytesleft;
inbytesleft = outbytesleft = data.length;
char *inbuf = (char *)data.bytes;
char *outbuf = malloc(sizeof(char) * data.length);
char *outptr = outbuf;
if (iconv(cd, &inbuf, &inbytesleft, &outptr, &outbytesleft)
== (size_t)-1) {
NSLog(@"this should not happen, seriously");
return nil;
}
NSData *result = [NSData dataWithBytes:outbuf length:data.length - outbytesleft];
iconv_close(cd);
free(outbuf);
return result;
}
NSData 转换成char*
NSData *data;
char *test=[data bytes];
char* 转换成NSData对象
byte* tempData = malloc(sizeof(byte)*16);
NSData *content=[NSData dataWithBytes:tempData length:16];
?NSString
?转?char *
1.?UTF8String
const char *cString = [string UTF8String];
2.?cStringUsingEncoding:
const char *cString = [string cStringUsingEncoding:NSUTF8StringEncoding];
3.?getCString:maxLength:encoding:
char cStringPtr[string.length * 3 + 1];
memset(cStringPtr, 0, sizeof(cStringPtr));
[string getCString:cStringPtr maxLength:sizeof(cStringPtr) encoding:NSUTF8StringEncoding];
UTF8
编码需要占用3个字节,因此这里需要*3
?char*
?转?NSString
1.?initWithUTF8String:
NSString *string = [[NSString alloc] initWithUTF8String:cString];
2.?initWithCString:encoding:
NSString *string = [[NSString alloc] initWithCString:cString encoding:NSUTF8StringEncoding];
3.?stringWithFormat:
NSString *string = [NSString stringWithFormat@"%s", cString];