iOS如何优雅的实现数据缓存

前言

1.每次做本地数据的缓存是都比较头痛。
2.用NSUserDefaults方便快捷，但是每次用key取的时候都担心key值写错，并且缓存数据过多时候会有一大堆key值，总感觉有点.......
3.用归档NSKeyedArchiver，需要实现NSCoding协议，每增加一个属性都要在协议里实现，万一忘记了，缓存就会失败。
4.本文用的方法是对NSUserDefaults的进一步封装，可以直接将服务器返回的数据字典NSDictionary缓存到本地，并且以模型方式返回。

1 创建模型类：类型UserUser

2 .h文件

#import 

@interface UserUser : NSObject

@property (nonatomic,copy)NSString * name;
@property (nonatomic,copy)NSString * sex;
@property (nonatomic,copy)NSString * age;

//单例方法，取出缓存的数据模型
+(instancetype)shareUserUser;
//用字典缓存用户数据
-(void)saveWithUserDic:(NSDictionary *)userDic;
//保存用户数据-（对当前模型修改后用）
-(void)save;
//移除本地缓存的数据
-(void)remove;

@end

3 .m文件

#import "UserUser.h"
#import "MJExtension.h"
#import 

#define cacheKey @"user"//缓存key自己随意修改

@implementation UserUser

+(instancetype)shareUserUser{
    
    static UserUser * user;
    if(user==nil){
        user=[[UserUser alloc]init];
        //获取本地缓存
        NSDictionary *userDic=[self objectForKey:cacheKey];
        if (userDic) {
            user=[UserUser mj_objectWithKeyValues:userDic];
        }
    }
    return user;
    
}
//用字典缓存用户数据
-(void)saveWithUserDic:(NSDictionary *)userDic{
    
    [self setObject:userDic forKey:cacheKey];
    UserUser*user=[UserUser mj_objectWithKeyValues:userDic];
    
    unsigned int count = 0;
    objc_property_t *properties = class_copyPropertyList([self class], &count);
    for (int i = 0; i < count; i++) {
        const char *name = property_getName(properties[i]);
        NSString *propertyName = [NSString stringWithUTF8String:name];
        id propertyValue = [user valueForKey:propertyName];
        if (propertyValue) {
            [self setValue:propertyValue forKey:propertyName];
        }
    }
    free(properties);
    
}
//保存用户数据-（对当前模型修改后可用）
- (void)save{
    //把当前数据模型转为字典存入本地
    NSDictionary *userDic=self.mj_keyValues;
    [self setObject:userDic forKey:cacheKey];
}
//移除本地缓存的数据
-(void)remove{
    [self setObject:@{} forKey:cacheKey];
    unsigned int count = 0;
    objc_property_t *properties = class_copyPropertyList([self class], &count);
    for (int i = 0; i < count; i++) {
        const char *name = property_getName(properties[i]);
        NSString *propertyName = [NSString stringWithUTF8String:name];
        [self setValue:nil forKey:propertyName];
    }
    free(properties);
}
#pragma mark NSUserDefaults操作
+(id)objectForKey:(NSString *)defaultName{
    NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
    return [userDefaults objectForKey:defaultName];
}
-(void)setObject:(id)value forKey:(NSString *)defaultName{
    NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
    [userDefaults setObject:value forKey:defaultName];
    [userDefaults synchronize];
}

4调用

NSDictionary *dic=@{@"name":@"kuipeng",
                        @"sex":@"男人",
                        @"abc":@"qwertyuiop",
                        @"bcd":@"asdfghjkl",
                        @"cdf":@"zxcvbnm"
                        };
    
    UserUser *user1=[UserUser shareUserUser];
    NSLog(@"1:%@",user1.name);
    NSLog(@"1:%@",user1.sex);
    NSLog(@"1:%@",user1.age);
    [user1 saveWithUserDic:dic];
    NSLog(@"2:%@",user1.name);
    NSLog(@"2:%@",user1.sex);
    NSLog(@"2:%@",user1.age);

5 打印

2019-06-21 11:02:39.431787+0800 AAA[76218:5882492] 1:songkuipeng
2019-06-21 11:02:39.431870+0800 AAA[76218:5882492] 1:男
2019-06-21 11:02:39.431886+0800 AAA[76218:5882492] 1:(null)
2019-06-21 11:02:39.433117+0800 AAA[76218:5882492] 2:kuipeng
2019-06-21 11:02:39.433175+0800 AAA[76218:5882492] 2:男人
2019-06-21 11:02:39.433190+0800 AAA[76218:5882492] 2:(null)

6 其他事项

项目中有用到MJExtension请自行添加