几种数据存储的基本用法

1、NSKeyedArchiver

        // 得到沙盒路径

        NSString *document = [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) lastObject];

        // 拼接整个文件路径

        NSString *file = [document stringByAppendingString:@"userDate"];

        // 进行对象的归档

        [NSKeyedArchiver archiveRootObject:account toFile:file];

到这里还不够，还有说明哪些属性要归档，哪些属性将来要解党。

首先需要遵守  NSCoding 协议。

@interface IWAccount : NSObject <NSCoding> 

/**
 *  从文件中读取对象的时候调用
 *
 */
- (id)initWithCoder:(NSCoder *)decoder
{
    if (self = [super init])
    {
        // 这里注意
        self.access_token = [decoder decodeObjectForKey:@"access_token"];
        self.expires_in = [decoder decodeInt64ForKey:@"expires_in"];
        self.remind_in = [decoder decodeInt64ForKey:@"remind_in"];
        self.uid = [decoder decodeInt64ForKey:@"uid"];
        self.expiresTime = [decoder decodeObjectForKey:@"expiresTime"];
    }
    return self;
}


/**
 *  将对象写入文件的时候调用
 *
 *  @param enaCoder
 */
- (void)encodeWithCoder:(NSCoder *)enaCoder
{
    [enaCoder encodeObject:self.access_token forKey:@"access_token"];
    [enaCoder encodeInt64:self.expires_in forKey:@"expires_in"];
    [enaCoder encodeInt64:self.remind_in forKey:@"remind_in"];
    [enaCoder encodeInt64:self.uid forKey:@"uid"];
    [enaCoder encodeObject:self.expiresTime forKey:@"expiresTime"];

}