Fundation框架（二）文件管理、字节缓存

文件管理

访问目录

//应用程序沙河目录
let path2 = NSHomeDirectory()
print(path2)
///Users/suntao/Library/Developer/CoreSimulator/Devices/580EC0C6-5025-42CD-A4E7-70C0CE8509F5/data/Containers/Data/Application/6A6B5D21-6FE1-401E-A5FF-03CE2BCA427B

let manager = FileManager.default
let urlForDocument = manager.urls(for: .documentDirectory, in:.userDomainMask)
let url = urlForDocument[0] as URL
print(url)
//file:///Users/suntao/Library/Developer/CoreSimulator/Devices/580EC0C6-5025-42CD-A4E7-70C0CE8509F5/data/Containers/Data/Application/6A6B5D21-6FE1-401E-A5FF-03CE2BCA427B/Documents/

path2 是url的上一级

目录操作

创建目录方法：withIntermediateDirectories为是否创建多级目录。attributes为设置目录的属性，比如目录的创建日期等。

let path2 = NSHomeDirectory()
let path = path2 + "/test/01" //注意前面的 "/" 线
do {
   try manager.createDirectory(atPath: path, withIntermediateDirectories: true, attributes: nil)
            
    } catch let err as NSError {
       print("文件创建失败: \(err)") 
}

删除目录或文件方法，要删除多级目录，需要删除最上级目录。

let path2 = NSHomeDirectory()
let path = path2 + "/test" //注意前面的 / 线
 //删除文件
do {
     if manager.fileExists(atPath: path) {
         try manager.removeItem(atPath: path)
      }
} catch let err as NSError {
     print("删除文件错误，错误信息为：\(err)")
}

文件操作 （文件写入、文件读取、文件复制、文件删除）

let fileManager = FileManager.default
let path1 = NSHomeDirectory()
let path2 = path1 + "/test"
print(path2)
        
    do {
       //创建文件夹
       try fileManager.createDirectory(atPath: path2, withIntermediateDirectories: true, attributes: nil)
            
       let filePath = path2 + "/01.text"
       let content = "写入文件内容"
            
       //写入文件方法
       //atomically：是否使用辅助文件，如果为true，则先写入到一个辅助文件，然后辅助文件再重新命名为目标文件。如果为false，则直接写入目标文件
       try content.write(toFile: filePath, atomically: true, encoding: String.Encoding.utf8)
            
       let copFilePath = path2 + "/02.text"
            
        //复制文件
       try fileManager.copyItem(atPath: filePath, toPath: copFilePath)
       let copFileContent = try String(contentsOfFile: copFilePath, encoding: String.Encoding.utf8)
       print("复制文本内容为：\(copFileContent)")
            
       //删除文件
       if fileManager.fileExists(atPath: copFilePath) {
            try fileManager.removeItem(atPath: copFilePath)
                print("删除文件成功")
        }
} catch let error as NSError {
            print("错误信息为：\(error)")
}

字节缓存

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let fileManager = FileManager.default
        let path1 = NSHomeDirectory()
        let path2 = path1 + "/dataTest"
        print(path2)
        let imageURL = "http://pic2.ooopic.com/12/42/25/02bOOOPIC95_1024.jpg"
        
        do {
            //创建文件夹
            try fileManager.createDirectory(atPath: path2, withIntermediateDirectories: true, attributes: nil)
            
            let url = URL(string: imageURL)
            let data = NSData(contentsOf: url!)
            
            //保存到本地的文件路径
            let imageFile = path2.appendingFormat("/image.jpg")
            data?.write(toFile: imageFile, atomically: true)
            
            //NSString -> NSData
            let content = "NSString -> NSData"
            let dataStr = content.data(using: String.Encoding.utf8)
            
            let dataOut = NSMutableData()
            dataOut.append(dataStr!)
            
            //将字节缓存数据写入文件
            let textFile = path2 + "/text.text"
            dataOut.write(toFile: textFile, atomically: true)
            
            //从文件读取字节缓存数据 NSString -> NSData
            let dataIn = NSData(contentsOfFile: textFile)
            let str = NSString(data: dataIn! as Data, encoding: String.Encoding.utf8.rawValue)
            print(str!)
            

        } catch let error as NSError {
            print("错误信息为：\(error)")
        }
        
    }
}