ios 文件管理获取文件属性读取文件

r囧r小猫 2023-10-18 08:42 70阅读 0赞

1、文件的创建
    -(IBAction) CreateFile
    {
    //对于错误信息
    NSError *error;
    // 创建文件管理器
    NSFileManager *fileMgr = [NSFileManager defaultManager];
    //指向文件目录
    NSString *documentsDirectory= [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
     //创建一个目录
    [[NSFileManager defaultManager]   createDirectoryAtPath: [NSString stringWithFormat:@"%@/myFolder", NSHomeDirectory()] attributes:nil];
     // File we want to create in the documents directory我们想要创建的文件将会出现在文件目录中
    // Result is: /Documents/file1.txt结果为：/Documents/file1.txt
    NSString *filePath= [documentsDirectory
    stringByAppendingPathComponent:@"file2.txt"];
    //需要写入的字符串
    NSString *str= @"iPhoneDeveloper Tipsnhttp://iPhoneDevelopTips,com";
    //写入文件
    [str writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
    //显示文件目录的内容
    NSLog(@"Documentsdirectory:  contentsOfDirectoryAtPath:documentsDirectory error:&error]);
     }
     
    
     
    2、对文件重命名
     
    对一个文件重命名
    想要重命名一个文件，我们需要把文件移到一个新的路径下。下面的代码创建了我们所期望的目标文件的路径，然后请求移动文件以及在移动之后显示文件目录。
    //通过移动该文件对文件重命名
    NSString *filePath2= [documentsDirectory
    stringByAppendingPathComponent:@"file2.txt"];
    //判断是否移动
    if ([fileMgr moveItemAtPath:filePath toPath:filePath2 error:&error] != YES)
    NSLog(@"Unable to move file: %@", [error localizedDescription]);
    //显示文件目录的内容
    NSLog(@"Documentsdirectory: %@",
    [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]);
    
     
     
    3、删除一个文件
     
     为了使这个技巧完整，让我们再一起看下如何删除一个文件： //在filePath2中判断是否删除这个文件 if ([fileMgr removeItemAtPath:filePath2 error:&error] != YES) NSLog(@"Unable to delete file: %@", [error localizedDescription]); //显示文件目录的内容 NSLog(@"Documentsdirectory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]); 一旦文件被删除了，正如你所预料的那样，文件目录就会被自动清空：
    这些示例能教你的，仅仅只是文件处理上的一些皮毛。想要获得更全面、详细的讲解，你就需要掌握NSFileManager文件的知识。
    
     
     
    4、删除目录下所有文件
     
    //获取文件路径 - (NSString *)attchmentFolder{
    NSString *document = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString *path = [document stringByAppendingPathComponent:@"Attchments"];
     NSFileManager *manager = [NSFileManager defaultManager];
     if(![manager contentsOfDirectoryAtPath:path error:nil]){
    [manager createDirectoryAtPath:path withIntermediateDirectories:NO attributes:nil error:nil];
    }
     return path;
    }
     
    --清除附件 BOOL result = [[NSFileManager defaultManager] removeItemAtPath:[[MOPAppDelegate instance] attchmentFolder] error:nil];
     
    
    5、获得文件的属性 -(void)getFileAttributes { NSFileManager *fileManager = [NSFileManager defaultManager]; NSString *path = @"/1ct.rtf"; NSDictionary *fileAttributes = [fileManager fileAttributesAtPath:path traverseLink:YES];     NSLog(@"@@"); if (fileAttributes != nil) {     NSNumber *fileSize;     NSString *fileOwner, *creationDate;     NSDate *fileModDate;     //NSString *NSFileCreationDate
        //文件大小     if (fileSize = [fileAttributes objectForKey:NSFileSize]) {         NSLog(@"File size: %qin", [fileSize unsignedLongLongValue]);     }
        //文件创建日期     if (creationDate = [fileAttributes objectForKey:NSFileCreationDate]) {         NSLog(@"File creationDate: %@n", creationDate);         //textField.text=NSFileCreationDate;     }
        //文件所有者     if (fileOwner = [fileAttributes objectForKey:NSFileOwnerAccountName]) {         NSLog(@"Owner: %@n", fileOwner);     }
        //文件修改日期     if (fileModDate = [fileAttributes objectForKey:NSFileModificationDate]) {         NSLog(@"Modification date: %@n", fileModDate);     }  } else {     NSLog(@"Path (%@) is invalid.", path);    } }
     
     
     
     
    //日期格式化 NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeStyle:NSDateFormatterNoStyle];
     //数字格式化
    NSNumberFormatter *numberFormatter =[[NSNumberFormatter alloc] init];
    [numberFormatter setPositiveFormat: @"#,##0.## bytes"];
    
    //获取文件属性
    NSDictionary *fileAttributes =[[NSFileManager defaultManager] fileAttributesAtPath: directoryPath traverseLink: YES];
    
    //获取文件的创建日期
    NSDate *modificationDate = (NSDate*)[fileAttributes objectForKey: NSFileModificationDate];
    
    //获取文件的字节大小
    NSNumber *fileSize = (NSNumber*)[fileAttributes objectForKey: NSFileSize];
     //格式化文件大小 nsstring A = [numberFormatter stringFromNumber: fileSize];
    
    //格式化文件创建日期
    NSstring B =[dateFormatter stringFromDate: modificationDate];
     
     [numberFormatter release];
    [dateFormatter release];
     
    
    
    6、读取文件内容操作
    - (void) loadFileContentsIntoTextView
    {
    //通过流打开一个文件
     
    NSInputStream *inputStream = [[NSInputStream alloc] initWithFileAtPath: filePath];
     
    [inputStream open];
     
     NSInteger maxLength = 128;
    uint8_t readBuffer [maxLength];
    //是否已经到结尾标识
    BOOL endOfStreamReached = NO;
    // NOTE: this tight loop will block until stream ends
    while (! endOfStreamReached)
    {
    NSInteger bytesRead = [inputStream read: readBuffer maxLength:maxLength];
    if (bytesRead == 0)
    {//文件读取到最后
    endOfStreamReached = YES;
    }
    else if (bytesRead == -1)
    {//文件读取错误
    endOfStreamReached = YES;
    }
    else
    {
    NSString *readBufferString =[[NSString alloc] initWithBytesNoCopy: readBuffer length: bytesRead encoding: NSUTF8StringEncoding freeWhenDone: NO];   
    //将字符不段的加载到视图
    [self appendTextToView: readBufferString];
    [readBufferString release];
    }
    }
    [inputStream close];
    [inputStream release];
    }