如何判断 NSURL 是否为目录

Question

我有一个 NSURL 对象。它具有文件系统元素的地址，它可以是文件或目录。我希望能够判断 NSURL 是目录还是文件。

这个我已经试过了，好像不行！

NSURL * temp ....... ;// it is initialized and has a valid value 
CFURLRef xx = (CFURLRef)CFBridgingRetain(temp);
if(CFURLHasDirectoryPath(xx)) NSLog(@"was a file");
else NSLog(@"was a folder");

Answer 1

NSNumber *isDirectory;

// this method allows us to get more information about an URL. 
// We're passing NSURLIsDirectoryKey as key because that's the info we want to know.
// Also, we pass a reference to isDirectory variable, so it can be modified to have the return value
BOOL success = [url getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:nil];

// If we could read the information and it's indeed a directory
if (success && [isDirectory boolValue]) {
    NSLog(@"Congratulations, it's a directory!");
} else {
    NSLog(@"It seems it's just a file.");
}

Answer 2

使用 Swift 5，您可以使用以下 macOS Playground 示例代码之一检查 URL 路径是代表目录还是常规文件。

---

#1。使用URL 的hasDirectoryPath 属性

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop")
print("is directory:", url.hasDirectoryPath)

---

#2。使用Filemanager的attributesOfItem(atPath:)方法

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop/File.pdf")
let attributes = try! FileManager.default.attributesOfItem(atPath: url.path)
if let type = attributes[FileAttributeKey.type] as? FileAttributeType {
    print("is file:", type == FileAttributeType.typeRegular)
}

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop")
let attributes = try! FileManager.default.attributesOfItem(atPath: url.path)
if let type = attributes[FileAttributeKey.type] as? FileAttributeType {
    print("is directory:", type == FileAttributeType.typeDirectory)
}

---

#3。使用URLResourceValues

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop")
if let resources = try? url.resourceValues(forKeys: [.isDirectoryKey]) {
    let isDirectory = resources.isDirectory ?? false
    print(isDirectory)
} else {
    print("No such file or directory")
}

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop/File.pdf")
if let resources = try? url.resourceValues(forKeys: [.isRegularFileKey]) {
    let isFile = resources.isRegularFile ?? false
    print(isFile)
} else {
    print("No such file or directory")
}

---

#4。使用FileManager 的fileExists(atPath:isDirectory:)

import Foundation

let url = URL(fileURLWithPath: "/Users/User/Desktop")
var isDirectory: ObjCBool = false
let fileExists = FileManager.default.fileExists(atPath: url.path, isDirectory: &isDirectory)
print("is directory:", fileExists && isDirectory.boolValue)

Answer 3

开始[iOS 9, macOS 10.11, tvOS 9.0, watchOS 2.0]，有hasDirectoryPath:

url.hasDirectoryPath

Answer 4

如果您知道文件 URL 已经标准化，那么您可以测试尾部斜杠。

-URLByStandardizingPath 将标准化文件 URL，包括在路径是目录时确保尾部斜杠。

这是一个显示-URLByStandardizingPath 添加斜杠的测试：

// Get a directory, any directory will do
NSURL *initialURL = [[NSBundle mainBundle] bundleURL];
NSString *initialString = [initialURL absoluteString];

// String the trailing slash off the directory
NSString *directoryString = [initialString substringToIndex:[initialString length] - 1];
NSURL *directoryURL = [NSURL URLWithString:directoryString];

XCTAssertFalse([[directoryURL absoluteString] hasSuffix:@"/"],
               @"directoryURL should not end with a slash");

XCTAssertTrue([[[directoryURL URLByStandardizingPath] absoluteString] hasSuffix:@"/"],
              @"[directoryURL URLByStandardizingPath] should end with a slash");

如您所见，[[[directoryURL URLByStandardizingPath] absoluteString] hasSuffix:@"/"] 是测试。

Answer 5

从 iOS 8 开始，在 Swift 3 中，有 isDirectory:

(try? url.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory ?? false