Swift获取沙盒中目录的一个分类

//
//  String+Category.swift

import UIKit

extension String{

/**
将当前字符串拼接到cache目录后面
*/
func cacheDir() -> String{
let path = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.CachesDirectory, NSSearchPathDomainMask.UserDomainMask, true).last!
return (path as NSString).stringByAppendingPathComponent((self as NSString).lastPathComponent)
}

/**
将当前字符串拼接到doc目录后面
*/
func docDir() -> String{
let path = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true).last!
return (path as NSString).stringByAppendingPathComponent((self as NSString).lastPathComponent)
}

/**
将当前字符串拼接到tmp目录后面
*/
func tmpDir() -> String{
let path = NSTemporaryDirectory() as NSString
return path.stringByAppendingPathComponent((self as NSString).lastPathComponent)
}
}

/*
原本：
let path = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.CachesDirectory, NSSearchPathDomainMask.UserDomainMask, true).last!
let filePath = (path as NSString).stringByAppendingPathComponent("account.plist")
*/
let filePath = "account.plist".cacheDir()