swift 数据存储

1.plist 存储

1.利用沙盒根目录拼接“Documents”字符串

//存储

func saveArray()

{

// 1.获得沙盒根路径，不管是真机还是模拟机，用它是最合适不过了

let home:NSString =NSHomeDirectory()

print(home)

// 2.document路径

let docPath:NSString = home.stringByAppendingPathComponent("Documents")

// 3.新建数据

let data:NSArray = ["jack","ffff"]

//3.文件路径

let filepath:NSString = docPath.stringByAppendingPathComponent("data.plist")

//4.存储数据

data.writeToFile(filepathasString, atomically:true)

}

//读取

@IBActionfunc read() {

//1.获得沙盒根路径

let home:NSString =NSHomeDirectory()

//2.document路径

let doctPath:NSString = home.stringByAppendingPathComponent("Document")

//3.文件路径

let filepath:NSString = doctPath.stringByAppendingPathComponent("data.plist")

//4.读取数据

let data:NSArray? =NSArray(contentsOfFile: filepathasString)

print("%@",data)

}

// 不建议采用，因为新版本的操作系统可能会修改目录名

2.利用NSSearchPathForDirectoriesInDomains获取路径

let array:
NSArray = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,NSSearchPathDomainMask.UserDomainMask,false)

//2.document路径

let documents:NSString = array.objectAtIndex(0)as!NSString

print(documents)

2.偏好设置

//存储

@IBActionfunc save()

{

// 1.利用NSUserDefaults,就能直接访问软件的偏好设置(Library/Preferences)

let defaults:NSUserDefaults =
NSUserDefaults.standardUserDefaults()

print(NSHomeDirectory())//能看到手机根目录

// 2.存储数据

defaults.setObject("mj", forKey:"account")

defaults.setObject("123", forKey:"pwd")

defaults.setInteger(10, forKey:"age")

defaults.setBool(true, forKey:"auto_login")

// 3.立刻同步

defaults.synchronize()

}

//读取

@IBActionfunc read()

{

let defaults:NSUserDefaults =
NSUserDefaults.standardUserDefaults()

let account = defaults.objectForKey("account")

let autoLogin:Bool = defaults.boolForKey("auto_login")

print("%@ -- %d", account, autoLogin)

}

• 注意：UserDefaults设置数据时，不是立即写入，而是根据时间戳定时地把缓存中的数据写入本地磁盘。所以调用了set方法之后数据有可能还没有写入磁盘应用程序就终止了。出现以上问题，可以通过调用synchornize方法强制写入[defaults
  synchornize];

3.NSKeyedArchiver归档(NSCoding)

class MJStudent:
NSObject,NSCoding

{

var no:
NSString!

var height:
Double!

var age:
Int32!

/**

*  将某个对象写入文件时会调用

*  在这个方法中说清楚哪些属性需要存储

*/

func encodeWithCoder(aCoder:
NSCoder)

{

print(NSHomeDirectory())

aCoder.encodeObject(self.no, forKey:
"no")

aCoder.encodeInt(self.age, forKey:
"age")

aCoder.encodeDouble(self.height, forKey:
"height")

}

/**

*  从文件中解析对象时会调用

*  在这个方法中说清楚哪些属性需要存储

*/

required
init?(coder aDecoder:
NSCoder)

{

self.no = aDecoder.decodeObjectForKey("no")
as! String

self.age = aDecoder.decodeIntForKey("age")

self.height = aDecoder.decodeDoubleForKey("height")

}

}

class ViewController:
UIViewController {

//存储

@IBAction
func save()

{

//1.新的模型对象

let stu:
MJStudent = MJStudent(coder: aDecoder: NSCoder)

stu.no =
"42343254"

stu.age =

stu.height =
1.55

// 2.归档模型对象

// 2.1.获得Documents的全路径

var doc:
NSString = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,
NSSearchPathDomainMask.UserDomainMask,
true).last

// 2.2.获得文件的全路径

var path:
NSString = doc.stringByAppendingPathComponent("stu.data")

// 2.3.将对象归档

NSKeyedArchiver.archiveRootObject(stu, toFile: path
as String)

}

//读取

@IBAction
func read()

{

// 1.获得Documents的全路径

var doc:
NSString = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory,
NSSearchPathDomainMask.UserDomainMask,
true).last!

// 2.获得文件的全路径

var path:
NSString = doc.stringByAppendingPathComponent("stu.data")

// 3.从文件中读取MJStudent对象

let stu:
MJStudent = NSKeyedUnarchiver.unarchiveObjectWithFile(path)

print("%@ %d %f", stu.no, stu.age,
stu.height)

}

}