IOS学习笔记之二十二(文件io)

1、NSData和NSMutableData和NSURL

NSData和NSMutableData表示oc的数据缓冲区

作用:

1)、对数据读取NSData

2)、输出NSData的数据

 

NSURL可以读取网络数据

 

 

2、MSFileManager管理文件和目录

作用：创建文件、删除文件、复制文件、移动文件

 

 

 

 

3、NSFileHandle处理文件io

我们可以用NSFileHandle写入数据到文件里面去、从文件里面读取数据、、

 

 

 

4、测试Demo

int main(int argc, char * argv[]) {@autoreleasepool {NSLog(@"当前用户名为:%@", NSUserName());NSLog(@"当前用户名为:%@", NSFullUserName());/**NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"https://www.baidu.com"]];NSLog(@"%ld", [data length]);char buff[200];[data getBytes:buff range:NSMakeRange(0, 20)];NSLog(@"%s", buff);//NSData to UTF-8 StringNSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];NSLog(@"========");NSLog(@"%@", str);**/ // NSString *documentsPath =[self getDocumentsPath];// rwxr-xr-x 3 ls access_bpf 96B Jul 20 21:47 Documents // drwxr-xr-x 5 ls access_bpf 160B Jul 20 20:45 Library // drwxr-xr-x 2 ls access_bpf 64B Jul 5 16:24 SystemData // drwxr-xr-x 2 ls access_bpf 64B Jul 5 16:24 tmp//获取沙盒根路径NSString *homePath = NSHomeDirectory();NSLog(@"home Paht is:%@", homePath);//获取 tmp目录NSString *tmpPath = NSTemporaryDirectory();NSLog(@"tmpPath is: %@", tmpPath);//获取Documents路径NSArray *docPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *path = [docPaths objectAtIndex:0];NSLog(@"document path:%@", path);NSFileManager *fileManager = [NSFileManager defaultManager];//创建文件夹NSString *dir = @"dir";NSString *dirPath = [path stringByAppendingPathComponent:dir];BOOL result = [fileManager createDirectoryAtPath:dirPath withIntermediateDirectories:YES attributes:nil error:nil];if (result){NSLog(@"make dir success");}else{NSLog(@"make dir fail");}//在document目录下面创建chenyu.txt文件，然后内容为hello, I am testing NSFileManager, my name is chenyuNSString *chenyuPath = [path stringByAppendingPathComponent:@"chenyu.txt"];NSString *content = @"hello, I am testing NSFileManager, my name is chenyu";BOOL isSuccess = [fileManager createFileAtPath:chenyuPath contents:[content dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];if (isSuccess) {NSLog(@"make chenyu.txt success");} else {NSLog(@"make chenyu.txt fail");}//读取chenyu.txt文件的内容NSString *value = [NSString stringWithContentsOfFile:chenyuPath encoding:NSUTF8StringEncoding error:nil];NSLog(@"chenyu.txt value is:%@", value);//新建chenyu1.txt 文件NSString *chenyuPath1 = [path stringByAppendingPathComponent:@"chenyu1.txt"];NSString *content1 = @"hello, I am testing NSFileManager, my name is chenyu1";BOOL result1 = [fileManager createFileAtPath:chenyuPath1 contents:[content1 dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];if (result1) {NSLog(@"make chenyu1.txt success");} else {NSLog(@"make chenyu1.txt fail");}//..../Data/Application/91D24910-B3CB-470C-9C62-D54E2815DF4E/Documents/ // -rw-r--r-- 1 ls access_bpf 52B Jul 20 23:18 chenyu.txt // -rw-r--r-- 1 ls access_bpf 53B Jul 20 23:18 chenyu1.txt // drwxr-xr-x 2 ls access_bpf 64B Jul 20 23:08 dir // -rw-r--r-- 1 ls access_bpf 33B Jul 20 22:12 iOS.txt//删除chenyu1.txt文件BOOL result2 = [fileManager removeItemAtPath:chenyuPath1 error:nil];if (result2) {NSLog(@"delete chenyu1.txt success");} else {NSLog(@"delete chenyu1.txt fail");} // -rw-r--r-- 1 ls access_bpf 52B Jul 20 23:23 chenyu.txt // drwxr-xr-x 2 ls access_bpf 64B Jul 20 23:08 dir // -rw-r--r-- 1 ls access_bpf 33B Jul 20 22:12 iOS.txt//新建chenyu2.txt 文件NSString *chenyuPath2 = [path stringByAppendingPathComponent:@"chenyu2.txt"]; // NSString *content2 = @"hello, I am testing NSFileManager, my name is chenyu2";BOOL res = [fileManager createFileAtPath:chenyuPath2 contents:nil attributes:nil];if (res) {NSLog(@"make chenyu2.txt success");} else {NSLog(@"make chenyu2.txt fail");}//NSFileHandle写数据到文件NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:chenyuPath2];[handle writeData:[@"this is useing NSHandle write data to chenyu2.txt" dataUsingEncoding:NSUTF8StringEncoding]];//NSFileHandle读取文件的内容NSFileHandle *readHandle = [NSFileHandle fileHandleForReadingAtPath:chenyuPath2];NSData *data = [readHandle readDataToEndOfFile];NSString *ss = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];NSLog(@"read data is:%@", ss);//运行结果目录下的文件 // rw-r--r-- 1 ls access_bpf 52B Jul 20 23:33 chenyu.txt // -rw-r--r-- 1 ls access_bpf 49B Jul 20 23:33 chenyu2.txt // drwxr-xr-x 2 ls access_bpf 64B Jul 20 23:08 dir // -rw-r--r-- 1 ls access_bpf 33B Jul 20 22:12 iOS.txt// 用vim打开chenyu2.txt内容如下 // this is useing NSHandle write data to chenyu2.txt} }

上面部分部分//是在终端输入ll命令后打印的信息

 

 

 

 

5、运行结果

2018-07-21 21:22:02.771753+0800 cyTest[31783:15710817] 当前用户名为: 2018-07-21 21:22:02.774191+0800 cyTest[31783:15710817] 当前用户名为: 2018-07-21 21:22:02.774973+0800 cyTest[31783:15710817] home Paht is:/Users/ls/Library/Developer/CoreSimulator/Devices/3FF9B833-FAF8-4C30-A855-3D40A4EAE8A6/data/Containers/Data/Application/BE126DC7-C827-4BD0-8BFC-A517ADC66E6C 2018-07-21 21:22:02.775214+0800 cyTest[31783:15710817] tmpPath is: /Users/ls/Library/Developer/CoreSimulator/Devices/3FF9B833-FAF8-4C30-A855-3D40A4EAE8A6/data/Containers/Data/Application/BE126DC7-C827-4BD0-8BFC-A517ADC66E6C/tmp/ 2018-07-21 21:22:02.775790+0800 cyTest[31783:15710817] document path:/Users/ls/Library/Developer/CoreSimulator/Devices/3FF9B833-FAF8-4C30-A855-3D40A4EAE8A6/data/Containers/Data/Application/BE126DC7-C827-4BD0-8BFC-A517ADC66E6C/Documents 2018-07-21 21:22:02.776600+0800 cyTest[31783:15710817] make dir success 2018-07-21 21:22:02.779185+0800 cyTest[31783:15710817] make chenyu.txt success 2018-07-21 21:22:02.780033+0800 cyTest[31783:15710817] chenyu.txt value is:hello, I am testing NSFileManager, my name is chenyu 2018-07-21 21:22:02.782365+0800 cyTest[31783:15710817] make chenyu1.txt success 2018-07-21 21:22:02.784235+0800 cyTest[31783:15710817] delete chenyu1.txt success 2018-07-21 21:22:02.785728+0800 cyTest[31783:15710817] make chenyu2.txt success 2018-07-21 21:22:02.786920+0800 cyTest[31783:15710817] read data is:this is useing NSHandle write data to chenyu2.txt

 

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