NSData

 

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

    NSString *documentPath = [pathArray firstObject];

    

    NSString *filePath = [documentPath stringByAppendingPathComponent:@"test.txt"];

    

    // 写入文件

    NSString *testStr = @"test....hello world!";

    [testStr writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:nil];

    

    // 读取文件

    NSData *data = [NSData dataWithContentsOfFile:filePath];

    NSString *dataStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"DATASTR = %@", dataStr);