将 NSData 写入文件的最简单方法

发布于 2024-07-16 04:34:25 字数 230 浏览 7 评论 0原文

NSData *data;
data = [self fillInSomeStrangeBytes];

我现在的问题是如何以最简单的方式将此数据写入文件。

（我已经有一个 NSURL file://localhost/Users/Coding/Library/Application%20Support/App/file.strangebytes）

原文

NSData *data;
data = [self fillInSomeStrangeBytes];

My question is now how I can write this data on the easiest way to an file.

(I've already an NSURL file://localhost/Users/Coding/Library/Application%20Support/App/file.strangebytes)

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水中月 2024-07-23 04:34:25

NSData 有一个名为 writeToURL:atomically: 的方法，它完全可以完成您想要做的事情。查看文档 < code>NSData 查看如何使用它。

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倦话 2024-07-23 04:34:25

请注意，将 NSData 写入文件是一个 IO 操作，可能会阻塞主线程。特别是当数据对象很大时。

因此建议在后台线程上执行此操作，最简单的方法是使用 GCD，如下所示：

// Use GCD's background queue
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
    // Generate the file path
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"yourfilename.dat"];

     // Save it into file system
    [data writeToFile:dataPath atomically:YES];
});

Notice that writing NSData into a file is an IO operation that may block the main thread. Especially if the data object is large.

Therefore it is advised to perform this on a background thread, the easiest way would be to use GCD as follows:

// Use GCD's background queue
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
    // Generate the file path
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"yourfilename.dat"];

     // Save it into file system
    [data writeToFile:dataPath atomically:YES];
});

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绝影如岚 2024-07-23 04:34:25

writeToURL:atomically: 或 writeToFile:atomically: 如果您有文件名而不是 URL。

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没企图 2024-07-23 04:34:25

您还有 writeToFile:options:error:或 writeToURL:options: error: 如果 NSData 因任何原因保存失败，它可以报告错误代码。例如：

NSError *error;

NSURL *folder = [[NSFileManager defaultManager] URLForDirectory:NSApplicationSupportDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:true error:&error];
if (!folder) {
    NSLog(@"%s: %@", __FUNCTION__, error);        // handle error however you would like
    return;
}

NSURL *fileURL = [folder URLByAppendingPathComponent:filename];
BOOL success = [data writeToURL:fileURL options:NSDataWritingAtomic error:&error];
if (!success) {
    NSLog(@"%s: %@", __FUNCTION__, error);        // handle error however you would like
    return;
}

You also have writeToFile:options:error: or writeToURL:options:error: which can report error codes in case the saving of the NSData failed for any reason. For example:

NSError *error;

NSURL *folder = [[NSFileManager defaultManager] URLForDirectory:NSApplicationSupportDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:true error:&error];
if (!folder) {
    NSLog(@"%s: %@", __FUNCTION__, error);        // handle error however you would like
    return;
}

NSURL *fileURL = [folder URLByAppendingPathComponent:filename];
BOOL success = [data writeToURL:fileURL options:NSDataWritingAtomic error:&error];
if (!success) {
    NSLog(@"%s: %@", __FUNCTION__, error);        // handle error however you would like
    return;
}

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