A1_数据持久化存储方案：plist、preference、NSKeyedArchiver、SQlite

一、NSUserDefaults（Preference偏好设置）
二、plist存储
三、归档NSKeyedArchiver
四、SQLite3
五、CoreData
六、FMDB(https://www.cnblogs.com/wendingding/p/3871848.html)

应用沙盒
Document:适合存储重要的数据， iTunes同步应用时会同步该文件下的内容,（比如游戏中的存档）
Library/Caches：适合存储体积大，不需要备份的非重要数据，iTunes不会同步该文件
Library/Preferences:通常保存应用的设置信息, iTunes会同步
tmp:保存应用的临时文件，用完就删除，系统可能在应用没在运行时删除该目录下的文件，iTunes不会同步

NSUserDefault
NSuserDefault适合存储轻量级的本地数据，支持的数据类型有：NSNumber，NSString，NSDate，NSArray，NSDictionary，BOOL，NSData
沙盒路径为 Library/Preferences
文件格式为 .plist

- (IBAction)userDefaultSave:(id)sender {
    NSArray *testArray = @[@"test1", @"test2", @"test3"];
    [[NSUserDefaults standardUserDefaults] setObject:testArray forKey:@"arrayKey"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}
- (IBAction)userDefaultLoad:(id)sender {
    NSArray *testArray = [[NSUserDefaults standardUserDefaults] objectForKey:@"arrayKey"];
    NSLog(@"%@", testArray);
}

获取沙盒路径
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentFilePath = paths.firstObject;

二、 plist存储

- (IBAction)plistSave:(id)sender {
    NSString *cachePath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES).firstObject;
    NSString *filePath = [cachePath stringByAppendingPathComponent:@"testPlist.plist"];
    
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    [dict setObject:@"ran" forKey:@"name"];
    [dict setObject:@"18" forKey:@"age"];
    [dict writeToFile:filePath atomically:YES];
}

- (IBAction)plistLoad:(id)sender {
    NSString *cachePath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES).firstObject;
    NSString *filePath = [cachePath stringByAppendingPathComponent:@"testPlist.plist"];
    
    NSDictionary *t = [NSDictionary dictionaryWithContentsOfFile:filePath];
    NSLog(@"%@",t);
}

三、归档NSKeyedArchiver
1.首先新建类，并遵守NSCoding协议
@interface Person : NSObject
2.实现协议方法

@implementation Person

- (instancetype)initWithCoder:(NSCoder *)coder
{
    self = [super init];
    if (self) {
        _name = [coder decodeObjectForKey:@"name"];
        _age = [coder decodeObjectForKey:@"age"];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)coder
{

    [coder encodeObject:self.name forKey:@"name"];
    [coder encodeObject:self.age forKey:@"age"];

}
@end
归档解档
- (IBAction)archive:(id)sender {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentFilePath = paths.firstObject;
    NSString *filePath = [documentFilePath stringByAppendingPathComponent:@"personModel"];
    
    Person *p1 = [[Person alloc] init];
    p1.name = @"ran";
    p1.age = @"18";
    
    [NSKeyedArchiver archiveRootObject:p1 toFile:filePath];
}

- (IBAction)unarchive:(id)sender {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentFilePath = paths.firstObject  ;
    NSString *filePath = [documentFilePath stringByAppendingPathComponent:@"personModel"];
    
    Person *p1 = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath] ;
    
    NSLog(@"%@", p1.name);
    NSLog(@"%@", p1.age);
}

数据库
https://www.jianshu.com/p/cd20f4a06c9d