Objective-C NSFileManager的使用

1. 回顾
   转大写
   -(NSString*)uppercaseString;
   -(NSString*)lowercaseString;
   -(NSString*)capitalizedString;
   -(BOOL)isEqualToString:(NSString*)aString;
   -(NSComparisonResult)compare:(NSString*)aString;
   -(BOOL)hasPrefix:(NSString*)aString;
   -(BOOL)hasSuffix:(NSString*)aString;
   -(NSRange)rangeOfString:(NSString*)aString;
   反向搜索
   -(NSRange)rangeOfString:(NSString*)aString options:NSBackwardsSearch;
   -(NSString*)substringFromIndex:(NSUInteger)from;
   -(NSString*)substringToIndex:(NSUInteger)to;
   -(NSString*)substringWithRange:(NSRange)range;
   -(unichar)characterAtIndex:(NSUInteger)index;
   字符串转换基础数据类型
   -(double)doubleValue;
   -(int)intValue;
   -(float)floatValue;
   -(char*)UTF8String;//一般在sqlite数据库时才会用到
   +(instancetype)array;
   +(instancetype)arrayWithObject:(id)anObject;
   +(instancetype)arrayWithObjects:(id)firstObje,...;
   +(instancetype)arrayWithArray:(NSArray*)array;
   +(id)arrayWithContentsOfFile:(NSString*)filepath;
   NSArray不能存储nil
   -(id)objectAtIndex:(NSUInteger)index;
   for(id obj in array){ }
   [arry enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop){  }];
   -(BOOL)writeToFile:(NSString*)path atomically:(BOOL) useAuxiliaryFile;
   -(BOOL)writeToURL:(NSURL*)url atomically:(BOOL)atomically;
   字符串拼接
   -(NSString*)componentsJoinedBytring:(NSString*)separator;
   -(NSArray*)componentsSeparatedByString:(NSString*)separator;
   +(instancetype)array;
   -(void)addObject:(id)object;
   -(void)insertObject:(id)anObject atIndex:(NSUInteger)index;
   -(void)removeObjectAtIndex:(NSUInteger) index;
   -(void)removeObjectsInRange:(NSRange)range;
   -(void)replaceObjectAtIndex:(NSUInteger)index withObject:(id)anObject;
   +(instancetype)dictionary;
   +(instancetype)dictionaryWithObject:(id)object forKey:(id<>)
   快速创建
   NSArray *array = @[@"",@"",@"",@""];
   NSDictioanry *dic = @{@"":@"",@"":@"",@"":@""};
   for(NSString *str in dict) {  }
   -(id)objectForKey:(NSUInteger)index;
   [dic dictionaryEnumerateObjectsUsingBlock:^(id key ,id value , BOOL *stop){}];
   [dic writeToFile:@"/Users/apple user/Desktop/dic.plist" atomically:YES];
   -(void)setObject:(id)anObject forKey:(id<NSCoping>)akey;
   -(void)removeObject:(NSString*)akey;
   
   


 2.NSFileManager的基本用法
   NSFileManager是用来管理文件系统的
   它可以用来进行常见的文件及文件夹操作(拷贝 ，剪切，创建等)


   NSFileManager使用单例模式
   使用defaultManager 方法尅获得那个单例模式
    
   -(BOOL)fileExistsAtPath:(NSString*)path;
   -(void)fileExistsAtPath:(NSString*)path isDirectory:(BOOL *)isDir;
   
   NSString *filePath = @"/Users/apple/Desktop/1.txt";
   NSString *directoryPath = @"/Users/apple/Desktop/";
   
   //fm该对象是一个单例对象
   NSFileManager *fm = [NSFileManager defaultManager];
   
   //1.文件是否存在
   BOOL isYES = [fm fileExistsAtPath:filePath];
    
   //2.判断是否是一个目录，还是一个文件夹
   BOOL isDir;
   [fm fileExistsAtPath:filePath isDirectory:&isDir];
   if(isDir)
NSLog(@"这是一个目录");
    
   //3.判断文件是否可读
   BOOL isRead;
   isRead = [fm isReadableFileAtPath:filepath];
   if(isRead)
NSLog(@"文件可读");
    
   //4.是否可写
   BOOL isWrite;
   isWrite = [fm isWritableFileAtPath:filePath];
   if(isWrite) 
NSLog(@"文件可写");
   
   //5.是否可删除
   BOOL isDelete;
   isDelete = [fm isDeletableFileAtPath:filePath];
   if(isDelete)
NSLog(@"文件可删除");

   
   NSFileManager 文件访问
   
   NSFileManager *fm = [NSFileManager defaultManager];
   NSString *filepath = @"/Users/apple/Desktop/a.plist";
   
   //1.获取文件属性信息 
   NSDictionary *dicInfo = [fm attributesOfItemAtPath:filepath error:nil];
   NSLog(@"%@",dicInfo);
   NSLog(@"%@",dicInfo["NSFileOwnerAccountName"]);
   
   //2.获取指定目录下的文件及子文件
   //以递归的方式，获取当前目录及子目录下的所有文件及文件夹
   filepath = @"/Users/apple/Desktop/test/";
   NSArray *arrSubPath = [fm subpathsAtPath:filepath];
   NSLog(@"%@",arrSubPath);
   
   //不是以递归的方式获取
   NSArray *arrDir = [fm subpathsOfDirectoryAtPath:filepath error:nil];
   NSLog(@"%@",arrDir);
    
   //3.获取指定目录下的文件及目录信息
   arrDir = [fm contentsOfDirectoryAtPath:filepath error:nil];
   NSLog(@"%@",arrDir);


  
   NSFileManger 创建目录及用法
   NSFileManager *fm = [NSFileManager defaultManager];
   
   //1.创建目录
   NSString *createPath = @"/Users/apple/Desktop/test1";
   NSDictionary *dicInfo = [NSDictionary dictionary];
   BOOL isYES = [fm createDirectoryAtPath:createPath withIntermediateDirectories:NO attributes:dicInfo error:nil];
   //注意：withIntermediateDirectories这个属性是路径中间的目录如果没有是否跟着创建
   if(isYES)
NSLog(@"目录创建成功！");
   
   //2.创建文件
   NSString *filepath = @"/Users/apple/Desktop/test/a.plist";
   NSDictionary *dicFile = [NSDictionary dictionary];
   //NSData是一个二进制数据的类，比如下载文件比较大，就需要一部分一部分下载
   NSString *strContent = @"这是我要存储的内容";
   NSData *data = [strContent dataUsingEncoding:NSUTF8String ];
   BOOL isYES = [fm createFileAtPath:filepath contents:data attributes:dicFile ];
   if(isYES)
NSLog(@"文件创建及写入成功！");
   
   //3.copy文件
   NSString *path1 = @"/Users/apple/Desktop/test/a1.plist";
   NSString *path2 = @"/Users/apple/Desktop/";
   BOOL isYes = [fm copyItemAtPath:path1 toPath:path2 error:nil];
   if(isYES)
  NSLog(@"拷贝文件成功！");
   
   //4.移动文件
   NSString *path1 = @"/Users/apple/Desktop/test/a1.plist";
   NSString *path2 = @"/Users/apple/Desktop/";
   BOOL isYES = [fm moveItemAtPath:path1 toPath:path2 error:nil];
   if(isYES)   
NSLog(@"移动文件成功");
   
   //5.删除文件
   NSString *dpath = @"/Users/apple/Desktop/test/a1.plist";
   BOOL isYES = [fm deleteItemAtPath:dpath error:nil];
   if(isYES)
NSLog(@"文件删除成功！");


















 3.NSFileManager文件下载思路
   例如：更新软件，过程就是远程下载文件，然后更新文件
   步骤：
   1.要下载的文件在服务器
   2.客服端连接服务器，通过一个地址，使用Http协议
   3.返回文件大小及信息到客户端，以二进制流的形式
   4.服务器把文件分解多个小文件
   
   要求：会断点续传，就是今天下载了一点，明天在来下载，那么明天还可以继续接着下载