归档文件
归档(称为序列化)是把对象转为字节码，以文件的形式存储到磁盘上；程序运行过程中或者当再次重写打开程序的时候，可以通过解归档（反序列化）还原这些对象。归档和解归档用于少量数据的持久化存储和读取。
归档和解归档常用API
//NSKeyedArchiver API
+ (BOOL)archiveRootObject:(id)rootObject toFile:(NSString *)path;
- (instancetype)initForWritingWithMutableData:(NSMutableData *)data;
- (void)finishEncoding;
- (void)encodeObject:(nullable id)objv forKey:(NSString *)key;
- (void)encodeBool:(BOOL)boolv forKey:(NSString *)key;
- (void)encodeInt:(int)intv forKey:(NSString *)key;
- (void)encodeFloat:(float)realv forKey:(NSString *)key;
- (void)encodeDouble:(double)realv forKey:(NSString *)key;
//NSKeyedUnarchiver API
+ (nullable id)unarchiveObjectWithData:(NSData *)data;
+ (nullable id)unarchiveObjectWithFile:(NSString *)path;
- (instancetype)initForReadingWithData:(NSData *)data;
- (void)finishDecoding;
- (nullable id)decodeObjectForKey:(NSString *)key;
- (BOOL)decodeBoolForKey:(NSString *)key;
- (int)decodeIntForKey:(NSString *)key;
- (float)decodeFloatForKey:(NSString *)key;
- (double)decodeDoubleForKey:(NSString *)key;
归档的方式：
- 针对对象进行归档（NSArray，NSDictionary等）
- 对自定义的内容进行归档
- 对自定义的对象进行归档
1、针对对象进行归档
- (void)objArchiver {
//归档（序列化）
NSArray *archiverAry = @[
@{@"Eugene" : @"ZhangYanJin"},
@{@"Chana" : @"LiChang"}
];
NSString *filePath = [self filePathWithName:@"Object"];
if ([NSKeyedArchiver archiveRootObject:archiverAry toFile:filePath]) {
NSLog(@"\n\n\n归档成功：路径%@",filePath);
}
//解归档 (反序列化)
NSArray *unArchiverAry = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
NSLog(@"\n解归档成功 %@",unArchiverAry);
/**
总结：
*优点：归档和解归档操作步骤简单方便
*缺点：一次只能归档一个对象，如果归档多个对象，需要分开麻烦，操作繁琐费时
*/
}
- (void)customContentArchiver {
//归档
//1、使用Data存放归档数据
NSMutableData *archiverData = [NSMutableData data];
//2、根据Data实例创建和初始化归档对象
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:archiverData];
//3、添加归档内容（设置键值对）
[archiver encodeObject:@"Eugene" forKey:@"name"];
[archiver encodeObject:@"man" forKey:@"sex"];
[archiver encodeInt:25 forKey:@"age"];
[archiver encodeObject:@[@"OC",@"Swift",@"Html"] forKey:@"laguage"];
[archiver encodeObject:@{@"favorite" : @"cook"} forKey:@"life"];
[archiver encodeCGPoint:CGPointMake(1.0, 2.0) forKey:@"point"];
//4、完成归档
[archiver finishEncoding];
//5、将归档的信息存储到磁盘上
NSString *filePath = [self filePathWithName:@"CustomContent"];
if ([archiverData writeToFile:filePath atomically:YES]) {
NSLog(@"\n\n\n归档成功：路径%@",filePath);
}
//解归档
//1、从磁盘读取文件，生成NSData实例
NSData *unarchiverData = [NSData dataWithContentsOfFile:filePath];
//2、根据Data实例创建和初始化解归档对象
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:unarchiverData];
//3、解归档，根据key值访问
NSString *name = [unarchiver decodeObjectForKey:@"name"];
NSDictionary *life = [unarchiver decodeObjectForKey:@"life"];
NSLog(@"\n解归档成功: %@ %@",name,life);
//4、完成解归档
[unarchiver finishDecoding];
/**
总结：
*优点：可以同时归档多个对象、以及不同类型的对象（如：Int、CGFloat、CGPoint）
*缺点：这里的对象都是基本类型数据，如果我想对自己定义类生成的实例对象进行归档，这样做将使操作又变得繁琐费时了
*/
}
- (void)customObjectArchiver {
//序列化和反序列化遵循NSCoding协议的自定义类
//归档
Person *person = [[Person alloc] init];
person.name = @"Eugene";
person.sex = @"man";
person.age = 25;
person.height = 175;
NSString *filePath = [self filePathWithName:@"CustomObject"];
if ([NSKeyedArchiver archiveRootObject:person toFile:filePath]) {
NSLog(@"\n\n\n归档成功：路径%@",filePath);
}
//解归档
Person *unArchiverObj = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
NSLog(@"\n解归档成功: %@ %@",unArchiverObj,unArchiverObj.name);
}
- (NSString *)filePathWithName:(NSString *)name {
name = [[NSString alloc] initWithFormat:@"%@.archiver",name];
//归档后的文件是加密的，所以归档文件的扩展名可以随意取,我这里后缀用archiver
return [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:name];
}
注意：
- 1、默认情况下，只能对NSDate, NSNumber, NSString, NSArray, or NSDictionary来进行归档。
- 2、若对自定义的对象进行归档，需要实现NSCoding协议，并实现NSCoding方法。
- NSCoding协议的方法：
- - (void)encodeWithCoder:(NSCoder *)aCoder;
- - (instancetype)initWithCoder:(NSCoder *)aDecoder;
- 3、如果用了继承，则子类一定要重写NSCoding协议的两个方法。
写在最后
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