关于使用文件的若干方法的总结

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首先，管理文件的一些方法，这里主要用到的是NSFileManager类，也用到了一些NSData类，NSData类创建的对象相当于是文件的缓存。

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *fName = @"testfile";
        NSFileManager *fm;
        NSDictionary *attr;
        NSData *fileData;

        //需要创建文件管理器的实例
        fm = [NSFileManager defaultManager];

        //首先确认测试文件存在
        if ([fm fileExistsAtPath:fName] == NO) {
            NSLog(@"File doesn‘t exist!!");
            return 1;
        }

        //创建一个副本
        if ([fm copyItemAtPath:fName toPath:@"newfile" error:NULL] == NO) {
            NSLog(@"File Copy Failed!");
            return 2;
        }

        //测试两个文件是否一致
        if([fm contentsEqualAtPath:fName andPath:@"newfile"] == NO){
            NSLog(@"Files are not Equal!");
            return 3;
        }

        //重命名副本
        if ([fm moveItemAtPath:@"newfile" toPath:@"newfile2" error:NULL] == NO) {
            NSLog(@"File rename Failed!");
            return 4;
        }

        //获取newfile2的大小
        if((attr = [fm attributesOfItemAtPath:@"newfile2" error:NULL]) == nil){
            NSLog(@"Couldn‘t get file attributes!");
            return 5;
        }
        NSLog(@"File size is %llu bytes",[[attr objectForKey:NSFileSize]unsignedLongLongValue]);

        //删除原始文件
        if ([fm removeItemAtPath:fName error:NULL] == NO) {
            NSLog(@"file removal failed!");
            return 6;
        }
        NSLog(@"All operations were successful");

        //显示新创建的文件内容
        NSLog(@"%@",[NSString stringWithContentsOfFile:@"newfile2" encoding:NSUTF8StringEncoding error:NULL]);

        //读取文件newfile2
        fileData = [fm contentsAtPath:@"newfile2"];

        if(fileData == nil){
            NSLog(@"File read faild!!");
        }

        //将缓存数据写入newfile3
        if ([fm createFileAtPath:@"newfile3" contents:fileData attributes:nil] == NO) {
            NSLog(@"Couldn‘t create the copy!");
        }

        NSLog(@"File copy was successful!");
    }
    return 0;
}

第二部分是关于文件目录的一些操作，比如说显示文件目录、显示目录下的文件等等：

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *dirName = @"testdir";
        NSString *path;
        NSFileManager *fm;
        NSDirectoryEnumerator *dirEnum;
        NSArray *dirArray;

        //创建文件管理器的实例
        fm = [NSFileManager defaultManager];

        //获取当前目录
        path = [fm currentDirectoryPath];
        NSLog(@"Current Directionary path is %@",path);

        //创建一个新的目录
        if ([fm createDirectoryAtPath:dirName withIntermediateDirectories:YES attributes:nil error:NULL] == NO) {
            NSLog(@"Couldn‘t create directory!");
            return 1;
        }

        //重新命名新的目录
        if ([fm moveItemAtPath:dirName toPath:@"newdir" error:NULL] == NO) {
            NSLog(@"Directionary rename failed!");
            return 2;
        }

        //更改目录到新的目录
        if ([fm changeCurrentDirectoryPath:@"newdir"] == NO) {
            NSLog(@"Change Directionart failed!");
            return 3;
        }

        //获取并显示当前的工作目录
        path =[fm currentDirectoryPath];
        NSLog(@"Current Directionary path is %@",path);

        //枚举目录
        dirEnum = [fm enumeratorAtPath:path];
        NSLog(@"Contents of %@",path);
        while ((path = [dirEnum nextObject]) != nil) {
            NSLog(@"%@",path);
        }

        //另一种枚举目录的方法
        dirArray = [fm contentsOfDirectoryAtPath:[fm currentDirectoryPath] error:NULL];
        NSLog(@"Contents using contentsOfDirectoryAtPath:error:");
        for (path in dirArray) {
            NSLog(@"%@",path);
        }

    }
    return 0;
}