数据持久化

//把数据存到硬盘

//iOS, 沙盒机制

//1.系统会为每个app, 分配一个文件夹(沙盒)

//2.每个app, 只能访问自己的沙盒; 系统的相册, 视频, 短信, 通讯录, 是可以访问的, 前提: 需要申请权限

//沙盒路径

//1.沙盒主目录, 名字无规律, 能避免别的应用访问

NSString *sandBoxPath = NSHomeDirectory();

NSLog(@"%@", sandBoxPath);

//1.

NSString *documentPath = [sandBoxPath stringByAppendingString:@"/Documents"];

//2.

//NSString *documentsPath1 = [sandBoxPath stringByAppendingPathComponent:@"Documents"];

//3.

//NSString *documengsPath2 = [NSString stringWithFormat:@"%@/Documents", sandBoxPath];

NSLog(@"%@", documentPath);

//沙盒主目录里有三个文件夹

//1.Documents: 存储一些比较重要的数据, 比如: 游戏存档, 用户信息等重要文件

//注: Documents中的文件, 在同步到iCloud的时候会一并同步进去, 所以要求Docements中的文件不能过大, 否则app没办法通过审核, 进而无法在appStore上线

//查找文件夹方法

//参数1: 文件夹名称

//参数2: 搜索的区域, 只在用户域(NSUserDomainMask)

//参数3: 返回的路径 是 相对路径no 还是 绝对路径yes, 使用绝对路径

NSString *documentsPath3 = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"%@", documentsPath3);

//2.Library, 存放视频, 图片, 音频, 缓存, 配置等文件

NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"%@", libraryPath);

//Library. 有两个子文件夹

//a.Caches, 缓存文件

NSString *cachesPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"%@", cachesPath);

//b.Preferences, 配置文件

//没有提供查找路径的方法, 不会直接在文件夹中对文件进行修改, 而是是Xcode中进行修改, 系统会自动同步到Preferences中去

//3.tmp, 临时文件文件, 比如zip压缩包

NSString *tmpPath = NSTemporaryDirectory();

NSLog(@"%@", tmpPath);

//4.包, 程序编译后, 最终形成一个包(比如*.app), 包内的文件是只读, 不能修改; Xcode中添加的文件, 比如图片, 文档等, 最终都会放到包中

NSString *bundlePath = [[NSBundle mainBundle] bundlePath];

NSLog(@"%@", bundlePath);

//数据持久化方式(这个是存到配置文件tmp中)

//1.文件读写

//2.NSUserDefaults

//3.归档

//4.数据库

//5.CoreData

//读取数据的方法

//documents文件路径

NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

//文件路径

NSString *filePath = [documentsPath stringByAppendingPathComponent:@"money.txt"];

NSError *error = nil;

NSString *moneyString = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&error];

if (error) {

NSLog(@"读取失败:%@", error);

}else{

NSLog(@"读取成功");

self.money = [moneyString integerValue];

self.label.text = [NSString stringWithFormat:@"%ld", self.money];

}

//1. 文件读写

//适用范围: 简单地数据, NSString, NSArray, NSDictionary, NSData以及他们的子类

//NSString

//写入文件

//- WriteToFile:atomically:encoding:error:

//读取文件

//initWithContentsOfFile: encoding: error:

//NSArray

//写入文件

//writeToFile: atomically:

//读取文件

//initWithContentsOfFile:(也有便利构造器)

NSArray *array = @[@"校花", @"校草", @"笑话"];

//写入文件

NSString *libraryPath1 = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) firstObject];

NSString *filePath1 = [libraryPath1 stringByAppendingPathComponent:@"array.txt"];

BOOL result = [array writeToFile:filePath1 atomically:YES];

if (result) {

NSLog(@"写入成功");

}else{

NSLog(@"写入失败");

}

//读取文件内容

NSArray *array1 = [[NSArray alloc] initWithContentsOfFile:filePath1];

//NSArray *array1 = [NSArray arrayWithContentsOfFile:filePath1];

for (NSString *string in array1) {

NSLog(@"%@", string);

}

[array1 release];

//NSDictionary

//写入文件

NSDictionary *dic = @{@"name" : @"校花", @"age" : @"18", @"class" : @"24"};

//写入文件

NSString *cachesPath1 = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];

NSString *filePath2 = [cachesPath1 stringByAppendingPathComponent:@"girl.plist"];

BOOL result2 = [dic writeToFile:filePath2 atomically:YES];

if (result2) {

NSLog(@"写入成功");

}else{

NSLog(@"写入失败");

}

//注: Array 和 Dictionary的数据, 建议存的文件使用后缀plist, 这样看起来比较直观

NSDictionary *dic2 = [[NSDictionary alloc] initWithContentsOfFile:filePath2];

NSLog(@"%@", dic2);

[dic2 release];

//NSDictionary

//写入文件

//writeToFile: atomically:

//读取文件

//initWithContentsOfFile:(也有便利构造器)

//NSData

//写入文件

//writeToFile: atomically:

//读取文件

//initWithContentsOfFile:(也有便利构造器)

NSString *str = @"iOS";

NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

NSString *tmpPath3 = NSTemporaryDirectory();

NSString *filePath3 = [tmpPath3 stringByAppendingPathComponent:@"data.txt"];

BOOL result3 = [data writeToFile:filePath3 atomically:YES];

if (result3) {

NSLog(@"写入成功");

}else{

NSLog(@"写入失败");

}

NSData *data3 = [[NSData alloc] initWithContentsOfFile:filePath3];

NSString *string3 = [[NSString alloc] initWithData:data3 encoding:NSUTF8StringEncoding];

NSLog(@"%@", string3);

//NSUserDefaults, 系统封装的一个快速写入内容的一个类, 单例模式, 继承于NSObject

//使用范围: BOOL, float, double, NSInteger

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

//写入文件

//BOOL

[userDefaults setBool:YES forKey:@"isFirst"];

[userDefaults setInteger:100 forKey:@"age"];

[userDefaults setFloat:99.9 forKey:@"price"];

[userDefaults setDouble:10.00 forKey:@"weight"];

[userDefaults setObject:@"zhangsan" forKey:@"name"];

//同步

[userDefaults synchronize];

//读取内容

BOOL boolValue = [userDefaults boolForKey:@"isFirst"];

NSLog(@"%d", boolValue);

NSInteger age = [userDefaults integerForKey:@"age"];

NSLog(@"%ld", age);

CGFloat weight =[userDefaults doubleForKey:@"weight"];

NSLog(@"%.2lf", weight);

CGFloat price = [userDefaults floatForKey:@"price"];

NSLog(@"%.2lf", price);

NSString *name =[userDefaults objectForKey:@"name"];

NSLog(@"%@", name);

//3.归档

//适用范围: 主要用于存自定义的数据类型, 比如Person

Person *person = [[Person alloc] init];

person.name = @"校花";

person.age = @"18";

person.gender = @"女";

//NSKeyedArchiver, 压缩工具, 继承于NSCoder, 把一个对象进行编码, 转化成NSData

NSMutableData *mData = [[NSMutableData alloc] initWithCapacity:0];

NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:mData];

//把person对象压进data

[archiver encodeObject:person forKey:@"girlFriend"];

//完成压缩

[archiver finishEncoding];

//tmp, 临时文件文件, 比如zip压缩包(写入文件（自定义一个路径）)

NSString *tmpPath1 = NSTemporaryDirectory();

NSString *filePath5 = [tmpPath1 stringByAppendingPathComponent:@"person.txt"];

BOOL result5 = [mData writeToFile:filePath5 atomically:YES];

if (result5) {

NSLog(@"写入成功");

}else{

NSLog(@"写入失败");

}

//反归档

NSData *mData1 = [[NSData alloc] initWithContentsOfFile:filePath5];

//NSKeyedUnarchiver, 解压工具, 从data数据提取对象

NSKeyedUnarchiver *unArchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:mData1];

Person *person1 = [unArchiver decodeObjectForKey:@"girlFriend"];

NSLog(@"%@", person1);

//归档 与 反归档

//多用于自定义数据类型, 比如Person, 并且能够进行归档的数据类型, 必须遵守, 实现编码和解码的方法, 对属性进行编码和解码, 编码和解码的key值必须相同

}