#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
#if 0
NSFileManager *fileManager = [NSFileManager defaultManager];
//后缀为txt并不一定就是文本文件,还是得看文件类型。
NSString *path = @"~/desktop/demoFile.txt";
//把@""字符串写到path里
[fileManager createFileAtPath:path contents:[@"hello world hellelellelelelelelelelele" dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
/*
NSError *error;
[fileManager createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:&error];
NSLog(@"errro:%@",error);
*/
BOOL isFileExi = [fileManager fileExistsAtPath:path isDirectory:nil];
//文件的属性放到字典里
NSDictionary *attris = [fileManager attributesOfItemAtPath:path error:nil];
//打印属性
NSLog(@"attris = %@",attris);
//打印文件大小
NSLog(@"fileSize = %@",attris[NSFileSize]);
//打印data的长度
NSData *data = [NSData dataWithContentsOfFile:path];
NSLog(@"%ld",data.length);
#endif
NSString *path = @"~/desktop/demoFile.txt";
//NSFileHandle像一个通道,使用完了记得关闭
//读取文件
NSFileHandle *readHandle = [NSFileHandle fileHandleForReadingAtPath:path];
//写入文件
NSFileHandle *writeHandle = [NSFileHandle fileHandleForWritingAtPath:path];
// NSData *data = [readHandle readDataToEndOfFile];
NSData *data = [readHandle readDataOfLength:5];
//每次读5个字节
data = [readHandle readDataOfLength:5];
NSLog(@"-->readhandle:%@",[[NSString alloc]initWithData:dataencoding:NSUTF8StringEncoding]);
// [writeHandle truncateFileAtOffset:1024*1024*2];
// [writeHandle seekToEndOfFile];
//从第三个字节开始往后写
[writeHandle seekToFileOffset:3];
//把"***"写入到文件里
[writeHandle writeData:[@"***" dataUsingEncoding:NSUTF8StringEncoding]];
//把"---"写入到文件
[writeHandle writeData:[@"---" dataUsingEncoding:NSUTF8StringEncoding]];
//关闭readHandle
[readHandle closeFile];
//关闭writeHandle
[writeHandle closeFile];
}
//写一个复制文件1到文件2的方法,思路如下:
- (void)copyFile:(NSString*)source to:(NSString*)target{
//创建一个目标文件
NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager createFileAtPath:target contents:nil attributes:nil];
//拿到源文件的属性,文件大小
NSDictionary *tempDict = [fileManager attributesOfItemAtPath:source error:nil];
NSNumber *tmpNum = tempDict[NSFileSize];
NSUInteger filelength = tmpNum.unsignedIntegerValue;
//次数为:字节长度/5
NSInteger count = filelength / 5;
//打开读写通道
NSFileHandle *readHandle = [NSFileHandle fileHandleForReadingAtPath:source];
NSFileHandle *writeHandle = [NSFileHandle fileHandleForWritingAtPath:target];
//用for循环写,每次读取5个字节,写入tempData
for (NSInteger i = 0; i<count; i++) {
NSData *tempData = [readHandle readDataOfLength:5];
[writeHandle writeData:tempData];
}
//如果字节有余,再读写一次
if(filelength % 5 != 0){
NSData *tempData = [readHandle readDataToEndOfFile];
[writeHandle writeData:tempData];
}
//关闭读写通道
[readHandle closeFile];
[writeHandle closeFile];
}
@end
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