在Swift中将文本附加到文档文件[重复]

Question

将文本写入文件文档时出现问题。 这是我的源代码：

 func getDocumentsDirectory() -> URL {
     let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
     return paths[0]
 }

 let fileName = getDocumentsDirectory().appendingPathComponent("LogFile.txt")

 do {
   try KML.soapRequest.xml.write(to: fileName, atomically: true, encoding: String.Encoding.utf8)
 } catch {
     print("Failed save")
 }

我想在文件“LogFile.txt”中插入文本，我是 swift 语言的新手。

感谢大家的帮助。

Answer 1

我在这里找到了您的问题：Append text or data to text file in Swift

• 如果文件存在，将附加到文本文件中。

• 如果文本文件不存在，将创建一个新文件。

  class Logger {
  
  static var logFile: URL? {
      guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return nil }
  
      let formatter = DateFormatter()
          formatter.dateFormat = "dd-MM-yyyy"
      let dateString = formatter.string(from: Date())
      let fileName = "\(dateString).log"
  
      return documentsDirectory.appendingPathComponent(fileName)
      }
  
  static func log(_ message: String, functionName: String = #function, filename: String = #file, line: Int = #line) {
       guard let logFile = logFile else {
          return
       }
  
       let className = filename.components(separatedBy: "/").last
  
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd HH:mm:ss.SSS "
        let timestamp = formatter.string(from: Date())
        guard let data = ("[\(timestamp)]  [\(className ?? "")] \(functionName)\(line): \(message)" + "\n").data(using: String.Encoding.utf8) else { return }
  
        if FileManager.default.fileExists(atPath: logFile.path) {
           if let fileHandle = try? FileHandle(forWritingTo: logFile)          {
                  fileHandle.seekToEndOfFile()
                  fileHandle.write(data)
                  fileHandle.closeFile()
           }
          } else {
             try? data.write(to: logFile, options: .atomicWrite)
          }
       }
  }