public static List<String> getColumnList(File file, int index, String sep,boolean ignore) {
		List<String> ret = new ArrayList<String>();
		BufferedReader br = null;

		try {
			// 构造BufferedReader对象
			br = new BufferedReader(new FileReader(file));

			int ln = 0;
			String line = null;
			while ((line = br.readLine()) != null) {
				ln++;
				if(ln%1000000==0){
					System.out.println("loading "+file.getName()+"\t"+ln+" lines.");
				}
				String[] cols = line.split(sep);
				if(cols.length>=(index+1)){
					String col = cols[index];
					ret.add(col);
				}else{
//					 //将出错line文本打印到控制台
					System.err.println("index overflow error at line "+ln+ ": "+line);
					if (!ignore){
						ret.add(null);
					}
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			// 关闭BufferedReader
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return ret;
	}