private static void ioRandomRead(final String fileName, int size) {
		long start = 0;
		int total = 0;
		int cnt = 0;
		try {
			File file = new File(fileName);
			RandomAccessFile fis = new RandomAccessFile(file, "r");

			byte buf[] = new byte[1024];
			
			int n = 0;

			//分成5块  每次 size/5 大小
			Map<Integer, Integer> seekMap = new HashMap<Integer, Integer>();
			int len = 1024 * 1024 * size / 102400;
			start = System.currentTimeMillis();
			for(int i = 102400 - 1; i >= 0; i--){
				n = 0;
				
				fis.seek(i * len);
				while (n != len) {
					n += fis.read(buf);
					total += 1024;
					cnt++;
				}
			}
			
			fis.close();
		} catch (IOException e) {
			System.err.println(e);
		}
		long end = System.currentTimeMillis();
		//System.out.println(total + " time: " + (end - start) + " count " + cnt);
		logger.info("io random read file " + size + "M cost: " + (System.currentTimeMillis() - start) + " ms count " + cnt);

	}