object-c nsdata 读取和写入二进制文件

-(void)test_file{

// 获取程序Documents目录路径

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

NSMutableString * path = [[NSMutableStringalloc]initWithString:documentsDirectory];

[path appendString:@"/fuck"];

NSString *temp =@"我现在要告诉我那你哈哈哈len 是不是Dang";

NSInteger i = [[temp dataUsingEncoding:NSUTF8StringEncoding] length];

NSMutableData * data = [[NSMutableDataalloc]init];

[data appendBytes:&i length:sizeof(i)];

[data appendData:[tempdataUsingEncoding:NSUTF8StringEncoding]];

[data writeToFile:pathatomically:YES];

NSInteger fuck = 0;

NSString * fff ;

NSData * reader = [NSDatadataWithContentsOfFile:path];

[reader getBytes:&fuck length:sizeof(fuck)];

fff = [[NSString alloc] initWithData:[reader subdataWithRange:NSMakeRange(sizeof(fuck) , fuck)]

encoding:NSUTF8StringEncoding];

NSLog(@"%@" , fff);

[fff release];

[path release];

[data release];

}