//存储图片的文件夹

var ljFilePath:String = NSHomeDirectory() + "/Documents/" + "LJImageCache/"

    /// 写文件
    ///
    /// - Parameters:
    ///   - fileName: 文件名称
    ///   - data: 数据data
    /// - Returns:
    func writeFile(_ fileName:String,_ data:NSData) -> Bool{
        
        //let filePath:String = NSHomeDirectory() + "/Documents/" + fileName.md5
        //return  data.write(toFile: filePath,atomically: true)
        if self.isExistsFile(path: ljFilePath)
        {
            guard let filePath : String = ljFilePath + fileName.md5 else{
                return false
            }
            return data.write(toFile: filePath,atomically: true)
        }
         return false
    }
    
    //读取文件 -（根据路径）
    func readFileFromCache(_ path:String) -> NSData?{
        
        if self.isExistsFile(path: ljFilePath)
        {
            let ljpatch = ljFilePath + path.md5
            
            var result:NSData?
            do{
                result = try NSData(contentsOfFile: ljpatch,options: Data.ReadingOptions.uncached)
            }catch{
                return nil
            }
            return result
        }
         return nil
    }
    
    //检测文件夹是否存在，不存在则创建一个文件夹
    func isExistsFile(path : String) -> Bool {
        let fileManager = FileManager.default
        let exist = fileManager.fileExists(atPath:path)
        if exist {
            //print("存在")
            return true
        }else{
            //print("不存在")
            //不存在则创建一个文件夹
            do{
            try fileManager.createDirectory(at: NSURL(fileURLWithPath:path,isDirectory: true) as URL,withIntermediateDirectories: true,attributes: nil)
            }catch{
                return false
            }
            return true
        }
    }