数据持久化

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ViewController.m

#import "ViewController.h"#import "Person.h"@interface ViewController ()@property (nonatomic,strong)UIImageView * imv;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    //    沙盒就是一个文件夹(说明一定有路径)//    获取沙盒路径    /*//    获取用户名    NSString * s = NSUserName();//    获取主路径    NSString * rootPath = NSHomeDirectoryForUser(s);    //    沙盒路径一直在变,(iOS8之前都是固定的)    NSLog(@"%@",rootPath);        //    other    NSString * rootPath1 = NSHomeDirectory();    NSLog(@"%@",rootPath1);    //    Documents会放变动很小的东西,不会轻易删除添加,所有会放数据库类似的东西,不要放缓存文件(电影之类的),不要放很大的东西,会连接到iCloud//    Library中的Cashes会放缓存的东西(退出后还有)//    tmp会放临时的东西,用完删,比如电影中的缓存,(退出后没了)//     这三个文件夹都是运行后才有东西,初始不带东西    */        //    获取三个路径    /*//    获取Documents路径//    作用:数据运行后产生,主要存储数据库等不长改变的数据文件.存在这里的文件会被备份.(下载的文件不能放在这)//    返回值是数组    NSString * documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];    NSLog(@"%@",documentsPath);    //    获取Caches路径//    作用:能放缓存文件,eg:音频,视频,图片:(不会被自动备份)    NSString * cachesPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];    NSLog(@"%@",cachesPath);    //    获取tmp路径//    作用:存放临时文件,程序下次启动不需要,退出清空    NSString* tmpPath = NSTemporaryDirectory();    NSLog(@"%@",tmpPath);    */            //    简单文件的写入    /*    //    字符串//    准备路径    NSString * documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];        NSLog(@"%@",documentsPath);    //    NSString,NSArray,NSDictionary,NSData//    文件路径    NSString * str1 = @"Hello,World";    NSString * filePath = [documentsPath stringByAppendingString:@"/hello.txt"];////    写入//    [str1 writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:nil];//    ////    读出//    NSString * s1 = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];//    //    NSLog(@"%@",s1);        //    数组    //    后缀随便写    NSString * filePath2 = [documentsPath stringByAppendingPathComponent:@"array.map3"];    NSArray * array1 = @[@"1",@"2",@"3"];    ////    写入////    [array1 writeToFile:filePath2 atomically:YES];//    ////    读//    NSArray *array2 = [NSArray arrayWithContentsOfFile:filePath2];//    NSLog(@"%@",array2);        //    字典    NSString * filePath3 = [documentsPath stringByAppendingPathComponent:@"dictionary.mp3"];    NSDictionary * dict1 = @{@"a":@"1",@"b":@"2"};    //    写入//    [dict1 writeToFile:filePath3 atomically:YES];    //    读出    NSDictionary * dict2 = [NSDictionary dictionaryWithContentsOfFile:filePath3];    NSLog(@"%@",dict2);    */        //    复杂对象的写入////    这种归档可以一次归档很多    /*//    Person * p1 = [[Person alloc]init];//    p1.name = @"贝爷";//    p1.age = 10;//////    准备一个可变Data//    NSMutableData * data = [NSMutableData data];//    ////    创建归档工具//    NSKeyedArchiver * archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];//    ////    开始归档//    [archiver encodeObject:p1 forKey:@"p1"];//    ////    完成归档//    [archiver finishEncoding];        //    存档后,要放入沙盒中        //    准备路径    NSString * documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];    NSLog(@"%@",documentsPath);    //    准备文件路径    NSString * filePath4 = [documentsPath stringByAppendingPathComponent:@"贝爷.m"];    ////    data写入//    [data writeToFile:filePath4 atomically:YES];    //    读出    NSData * data1 = [NSData dataWithContentsOfFile:filePath4];    //    反归档    NSKeyedUnarchiver * unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data1];    //    转换成对象    Person * p2 = [unarchiver decodeObjectForKey:@"p1"];    //    反归档完成    [unarchiver finishDecoding];        NSLog(@"%@ == %ld",p2.name,p2.age);    */        //    这种方便,但是一次只能归档一个(不常用)    /*    //    准备路径    NSString * documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];    NSLog(@"%@",documentsPath);    //    拼接路径    NSString * filePath5 = [documentsPath stringByAppendingPathComponent:@"person"];        Person * p3 = [[Person alloc]init];    p3.name = @"六娃";    p3.age = 20;    //    存//    [NSKeyedArchiver archiveRootObject:p3 toFile:filePath5];//    取    Person *p4 = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath5];    NSLog(@"%@ = %ld",p4.name,p4.age);    */        //    NSUserDefaults//    用来存储不是很大的东西    /*    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];    //    存//    [ud setObject:@"yan3" forKey:@"lanou"];////    同步数据//    [ud synchronize];    //    取//    NSLog(@"%@",[ud objectForKey:@"lanou"]);    */        //    导航页测试    /*    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];        NSString * s = [ud objectForKey:@"first"];    if (s == nil) {        self.imv = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"hehe.png"]];        self.imv.frame = self.view.bounds;        [self.view addSubview:_imv];                [ud setObject:@"NO" forKey:@"first"];    }    */    //    NSFileManager    //    路径    NSString * cachesPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];    NSLog(@"%@",cachesPath);    //    创建文件管理对象    NSFileManager * fm = [NSFileManager defaultManager];    //    创建文件夹//    [fm createDirectoryAtPath:[cachesPath stringByAppendingPathComponent:@"test"] withIntermediateDirectories:NO attributes:nil error:nil];    //    更改文件名//    [fm moveItemAtPath:[cachesPath stringByAppendingPathComponent:@"test"] toPath:[cachesPath stringByAppendingPathComponent:@"Demo"] error:nil];        //    移动文件位置//    [fm moveItemAtPath:[cachesPath stringByAppendingPathComponent:@"00/test"] toPath:[cachesPath stringByAppendingPathComponent:@"Demo/test"] error:nil];        //    删除文件//    [fm removeItemAtPath:[cachesPath stringByAppendingPathComponent:@"Demo"] error:nil];        //    判断一个文件是否存在        BOOL i = [fm fileExistsAtPath:@"asdad"];    NSLog(@"%d",i);    }- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

Person.h

#import <Foundation/Foundation.h>//一个类是否可以被归档反归档,要看是否遵循NSCoding协议@interface Person : NSObject<NSCoding>@property (nonatomic,copy)NSString * name;@property (nonatomic,assign)NSInteger age;@end

Person.m

#import "Person.h"@implementation Person//编码- (void)encodeWithCoder:(NSCoder *)aCoder{        [aCoder encodeObject:self.name forKey:@"p_name"];    [aCoder encodeInteger:self.age forKey:@"p_age"];}//反编码- (id)initWithCoder:(NSCoder *)aDecoder{        if (self = [super init]) {        self.name = [aDecoder decodeObjectForKey:@"p_name"];        self.age = [aDecoder decodeIntegerForKey:@"p_age"];    }    return self;}@end

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