iOS有以下几种数据持久化方式

• NSUserDefault （无法保存自定义对象）
• plist表 （无法保存自定义对象）
• 归档 实现NSCoding协议 可以保存自定义对象
• SQLite3 框架FMDB http://www.jianshu.com/writer#/notebooks/10081699/notes/10839261
• CoreData 简单使用http://www.jianshu.com/p/1cd286a7d32f
• KeyChain

一.NSUserDafault

    NSUserDefaults *userInfo = [NSUserDefaults standardUserDefaults];
    NSLog(@"%@  %ld  %@",[userInfo objectForKey:@"age"],[userInfo integerForKey:@"tizhong"],[userInfo objectForKey:@"family"]);

    [userInfo setObject:@33 forKey:@"age"];
    [userInfo setInteger:88 forKey:@"tizhong"];
    [userInfo setObject:@[@"dad",@"mom",@"wife"] forKey:@"family"];
    [userInfo synchronize];

输出

2017-03-31 23:25:48.501 CoreData[6987:560191] 33  88  (
    dad,
    mom,
    wife
)

二.plist表

能存进plist表的数据类型
NSArray;
NSMutableArray;
NSDictionary;
NSMutableDictionary;
NSData;
NSMutableData;
NSString;
NSMutableString;
NSNumber;
NSDate;

    NSString *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
    NSString *fileName = [path stringByAppendingPathComponent:@"family.plist"];
    NSArray *array = @[@"dad",@"mom",@"wife",@22,[@[@11,@22,@33]mutableCopy],[NSDate date]];
    [array writeToFile:fileName atomically:YES];

    NSArray *result = [NSArray arrayWithContentsOfFile:fileName];
    NSLog(@"%@", result);

输出

 (
    dad,
    mom,
    wife,
    22,
        (
        11,
        22,
        33
    ),
    "2017-03-31 15:39:26 +0000"
)

三.归档

@class Dog;

@interface Man : NSObject<NSCoding>
@property (nonatomic,copy) NSString *name;
@property (nonatomic,assign) NSInteger age;
@property (nonatomic,copy) Dog *dog;

@end
@implementation Man
@synthesize name;
@synthesize age;
@synthesize dog;

- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:name forKey:@"name"];
    [aCoder encodeInteger:age forKey:@"age"];
    [aCoder encodeObject:dog forKey:@"dog"];
}
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder
{
    if(self = [super init])
    {
        self.name = [aDecoder decodeObjectForKey:@"name"];
        self.age = [aDecoder decodeIntegerForKey:@"age"];
        self.dog = [aDecoder decodeObjectForKey:@"dog"];
    }
    return self;
}// NS_DESIGNATED_INITIALIZER

@end

参数dog类定义

@interface Dog : NSObject<NSCoding,NSCopying>
@property (nonatomic,copy) NSString *name;

@end
@implementation Dog
@synthesize name;
- (id)copyWithZone:(nullable NSZone *)zone
{
    Dog *samo = [[self class] allocWithZone:nil];
    samo.name = self.name;
    return samo;
}
- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:name forKey:@"name"];
}
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder
{
    if(self = [super init])
    {
        self.name = [aDecoder decodeObjectForKey:@"name"];
    }
    return self;
}// NS_DESIGNATED_INITIALIZER

test代码

-(void)testKeyedArchiver
{
    
    NSString *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
    NSString *fileName = [path stringByAppendingPathComponent:@"some.data"];

    Dog *dog = [[Dog alloc] init];
    dog.name = @"heihei";

    Man *m = [[Man alloc] init];
    m.name = @"me";
    m.age = 20;
    m.dog = dog;
    [NSKeyedArchiver archiveRootObject:m toFile:fileName];
    
    Man *me = [NSKeyedUnarchiver unarchiveObjectWithFile:fileName];
    
    
}

读取的归档

四.SQLite3

http://www.jianshu.com/writer#/notebooks/10081699/notes/10839261

五.CoreData

http://www.jianshu.com/p/1cd286a7d32f

六.KeyChain

manage

@interface QBZKeyChainManage : NSObject
//根据service创建用于操作keychain的dic
+ (NSMutableDictionary *)keyChainQueryDictionaryWithService:(NSString *)service;
//添加数据
+ (BOOL)addData:(id)data forService:(NSString *)service;
//查找数据
+ (id)queryDataWithService:(NSString *)service;
//更新数据
+ (BOOL)updateData:(id)data forService:(NSString *)service;
//删除数据
+ (BOOL)deletaDataWithService:(NSString *)service;

@implementation QBZKeyChainManage
//根据service创建用于操作keychain的dic
+ (NSMutableDictionary *)keyChainQueryDictionaryWithService:(NSString *)service
{
    NSMutableDictionary *keyChainQueryDictionary = [@{} mutableCopy];
    [keyChainQueryDictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
    [keyChainQueryDictionary setObject:service forKey:(id)kSecAttrService];
    [keyChainQueryDictionary setObject:service forKey:(id)kSecAttrAccount];
    return keyChainQueryDictionary;
}
//添加数据
+ (BOOL)addData:(id)data forService:(NSString *)service
{
    NSMutableDictionary *keyChainQueryDictionary = [QBZKeyChainManage keyChainQueryDictionaryWithService:service];
    SecItemDelete((CFDictionaryRef)keyChainQueryDictionary);
    [keyChainQueryDictionary setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];
    OSStatus status = SecItemAdd((CFDictionaryRef)keyChainQueryDictionary, NULL);
    if(status == noErr)
    {
        return YES;
    }
    return NO;
}
//查找数据
+ (id)queryDataWithService:(NSString *)service
{
    id result;
    NSMutableDictionary *keyChainQuery = [self keyChainQueryDictionaryWithService:service];
    [keyChainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
    [keyChainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
    CFDataRef keyData = NULL;
    if (SecItemCopyMatching((CFDictionaryRef)keyChainQuery, (CFTypeRef *)&keyData) == noErr) {
        @try {
            result = [NSKeyedUnarchiver  unarchiveObjectWithData:(__bridge NSData *)keyData];
        }
        @catch (NSException *exception) {
            NSLog(@"不存在数据");
        }
        @finally {
            
        }
    }
    if (keyData) {
        CFRelease(keyData);
    }
    return result;
}
//更新数据
+ (BOOL)updateData:(id)data forService:(NSString *)service
{
    NSMutableDictionary *searchDictionary = [self keyChainQueryDictionaryWithService:service];
    
    if (!searchDictionary) {
        return NO;
    }
    
    NSMutableDictionary *updateDictionary = [[NSMutableDictionary alloc] init];
    [updateDictionary setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];
    OSStatus status = SecItemUpdate((CFDictionaryRef)searchDictionary,
                                    (CFDictionaryRef)updateDictionary);
    if (status == errSecSuccess) {
        return YES;
    }
    return NO;
}
//删除数据
+ (BOOL)deletaDataWithService:(NSString *)service
{
    NSMutableDictionary *keyChainDictionary = [self keyChainQueryDictionaryWithService:service];
    OSStatus status = SecItemDelete((CFDictionaryRef)keyChainDictionary);
    if (status == noErr) {
        return YES;
    }
    return NO;
}

@end

test

-(IBAction)add:(id)sender
{
    NSMutableDictionary *dic = [QBZKeyChainManage queryDataWithService:@"testData"];
    if(dic)
    {
        self.label.text = [dic objectForKey:@"title"];
    }else{
        NSMutableDictionary *dic = [@{} mutableCopy];
        [dic setObject:@"测试" forKey:@"title"];
        [QBZKeyChainManage addData:dic forService:@"testData"];
    }
}

两个app之间共享数据

Keychain设置