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 String
NSString *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 chenyu
NSString *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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