如何从文件Swift中读取

Question

func writeToFile(content: String, fileName: String) {

    let contentToAppend = content+"\n"
    let filePath = NSHomeDirectory() + "/Documents/" + fileName

    //Check if file exists
    if let fileHandle = NSFileHandle(forWritingAtPath: filePath) {
        //Append to file
        fileHandle.seekToEndOfFile()
        fileHandle.writeData(contentToAppend.dataUsingEncoding(NSUTF8StringEncoding)!)
    }
    else {
        //Create new file
        do {
            try contentToAppend.writeToFile(filePath, atomically: true, encoding: NSUTF8StringEncoding)
        } catch {
            print("Error creating \(filePath)")
        }
    }
}

我有那个允许我调用这个函数并且写入文件的代码。现在我不知道如何阅读这个文件。我想在多行文本框中显示文件内容。有人可以帮助我使用此代码的读取功能吗？