NSFileManager文件操作的十個小功能

NSFileManager是一個單列類，也是一個文件管理器。可以通過NSFileManager創建文件夾、創建文件、寫文件、讀文件內容等等基本功能。

下面將介紹NSFileManager文件操作的十個小功能。我們在Documents里面進行舉例，首先是獲取Documents的路徑。這個在iOS開發之沙盒機制（SandBox)已經詳細講解過了。獲取Documents路徑方法如下：

- (NSString *)getDocumentsPath
{
    //獲取Documents路徑
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [paths objectAtIndex:0];
    NSLog(@"path:%@", path);
    return path;
} 

創建文件夾

-(void)createDirectory{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSDirectory = [documentsPath stringByAppendingPathComponent:@"iOS"];
    BOOL isSuccess = [fileManager createDirectoryAtPath:iOSDirectory withIntermediateDirectories:YES attributes:nil error:nil];
    if (isSuccess) {
        NSLog(@"success");
    } else {
        NSLog(@"fail");
    }
} 

創建文件

-(void)createFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager createFileAtPath:iOSPath contents:nil attributes:nil];
    if (isSuccess) {
        NSLog(@"success");
    } else {
        NSLog(@"fail");
    }
} 

寫文件

-(void)writeFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = @"我要寫數據啦";
    BOOL isSuccess = [content writeToFile:iOSPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
    if (isSuccess) {
        NSLog(@"write success");
    } else {
        NSLog(@"write fail");
    }
} 

讀取文件內容

-(void)readFileContent{
    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = [NSString stringWithContentsOfFile:iOSPath encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"read success: %@",content);
} 

判斷文件是否存在

- (BOOL)isSxistAtPath:(NSString *)filePath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:filePath];
    return isExist;
} 

計算文件大小

- (unsigned long long)fileSizeAtPath:(NSString *)filePath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:filePath];
    if (isExist){
        unsigned long long fileSize = [[fileManager attributesOfItemAtPath:filePath error:nil] fileSize];
        return fileSize;
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
} 

計算整個文件夾中所有文件大小

- (unsigned long long)folderSizeAtPath:(NSString*)folderPath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:folderPath];
    if (isExist){
        NSEnumerator *childFileEnumerator = [[fileManager subpathsAtPath:folderPath] objectEnumerator];
        unsigned long long folderSize = 0;
        NSString *fileName = @"";
        while ((fileName = [childFileEnumerator nextObject]) != nil){
            NSString* fileAbsolutePath = [folderPath stringByAppendingPathComponent:fileName];
            folderSize += [self fileSizeAtPath:fileAbsolutePath];
        }
        return folderSize / (1024.0 * 1024.0);
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
} 

刪除文件

-(void)deleteFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager removeItemAtPath:iOSPath error:nil];
    if (isSuccess) {
        NSLog(@"delete success");
    }else{
        NSLog(@"delete fail");
    }
} 

移動文件

- (void)moveFileName
{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
} 

重命名

- (void)renameFileName
{
    //通過移動該文件對文件重命名
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"rename.txt"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
} 

以上文件操作代碼都在iOSStrongDemo，可以直接通過git拉下來進行測試。關于NSFileManager的用法還有很多，一起接續探索吧！