生成csv文件 可以使用excell读取

- (IBAction)btnPressed:(id)sender {

//文档地址    

    NSArray *documents =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);

    NSString *docementDir = [documentsobjectAtIndex:0];

    NSString *filePath = [docementDirstringByAppendingPathComponent:@"student.csv"];

//初始化数据

    [selfformatDates];

//创建文件

    [selfcreateFile:filePath];

//导出数据

    [selfexportCSV:filePath];

}

- (void)createFile:(NSString *)fileName {

    NSFileManager *fileManager = [NSFileManagerdefaultManager];

    [fileManager removeItemAtPath:fileNameerror:nil];

    if (![fileManagercreateFileAtPath:fileNamecontents:nilattributes:nil]) {

        NSLog(@"不能创建文件");

    }

}

- (void)exportCSV:(NSString *)fileName {

    

    NSOutputStream *output = [[NSOutputStreamalloc]initToFileAtPath:fileNameappend:YES];

    [output open];

    if (![outputhasSpaceAvailable]) {

        NSLog(@"没有足够空间");

    }

    else

    {

        NSString *head =@"学号,姓名\n";

        constuint8_t *headerString = (constuint8_t *)[head cStringUsingEncoding:NSUTF8StringEncoding];

        NSInteger headerLength = [headlengthOfBytesUsingEncoding:NSUTF8StringEncoding];

        NSInteger result = [outputwrite:headerStringmaxLength:headerLength];

        if (result <=0) {

            NSLog(@"写入错误");

        }

        for (long i =0; i <_mutArr.count; i ++) {

            Student *stu =_mutArr[i];

            NSString *row = [NSStringstringWithFormat:@"%@,%@\n",stu.name,stu.num];

            constuint8_t *rowString = (constuint8_t *)[row cStringUsingEncoding:NSUTF8StringEncoding];

            NSInteger rowLength = [rowlengthOfBytesUsingEncoding:NSUTF8StringEncoding];

            result = [output write:rowStringmaxLength:rowLength];

            if (result <=0) {

                NSLog(@"无法写入内容");

            }

        }

        [output close];

    }

}

- (void)formatDates

{

    _mutArr = [NSMutableArrayarray];

    for (long i =0; i <40; i ++) {

        Student *stu = [[Studentalloc]init];

        stu.name = [NSStringstringWithFormat:@"Name啦啦啦==%ld",i];

        stu.num = [NSStringstringWithFormat:@"%ld",i*10];

        [_mutArraddObject:stu];

    }

    

}