public Map<String,Double> getCateWordsProb(String strDir) throws IOException{
		Map<String,Double> cateWordsProb = new TreeMap<String,Double>();
		File sampleFile = new File(strDir);
		File [] sampleDir = sampleFile.listFiles();
		String word;
		for(int i = 0;i < sampleDir.length; i++){
			File [] sample = sampleDir[i].listFiles();
			for(int j = 0; j < sample.length; j++){
				FileReader samReader = new FileReader(sample[j]);
				BufferedReader samBR = new BufferedReader(samReader);
				while((word = samBR.readLine()) != null){
					String key = sampleDir[i].getName() + "_" + word;
					if(cateWordsProb.containsKey(key)){
						double count = cateWordsProb.get(key) + 1.0;
						cateWordsProb.put(key, count);
					}
					else {
						cateWordsProb.put(key, 1.0);
					}
				}
			}
		}
		return cateWordsProb;	
	}