//第一种方法： NSFileManager实例方法读取数据
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDesktopDirectory, NSUserDomainMask, YES);
NSString* thepath = [paths lastObject];
thepath = [thepath stringByAppendingPathComponent:@"fd_list.txt"];
NSLog(@"桌面目录：%@", thepath);
NSFileManager* fm = [NSFileManager defaultManager];
NSData* data = [[NSData alloc] init];
data = [fm contentsAtPath:thepath];
NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
         
         
//第二种方法： NSData类方法读取数据
data = [NSData dataWithContentsOfFile:thepath];
NSLog(@"NSData类方法读取的内容是：%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
         
         
//第三种方法： NSString类方法读取内容
NSString* content = [NSString stringWithContentsOfFile:thepath encoding:NSUTF8StringEncoding error:nil];
NSLog(@"NSString类方法读取的内容是：\n%@",content);
         

//第四种方法： NSFileHandle实例方法读取内容
NSFileHandle* fh = [NSFileHandle fileHandleForReadingAtPath:thepath];
data = [fh readDataToEndOfFile];
NSLog(@"NSFileHandle实例读取的内容是：\n%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);