Java arraylist重复使用问题

arraylist同一个实例重复使用时，需要使用clear()及时清空，否则会在上次的结果后面添加项。

List<Double> weightsList = new ArrayList<Double>();

for(int i=0;i<4;i++){
        fs = FileSystem.get(URI.create(statePath[i]), conf);
        hdfsInStream = fs.open(new Path(statePath[i]));
        br = new BufferedReader(new InputStreamReader(hdfsInStream));
        int j = 0;
        while((line = br.readLine()) != null){
                if(j == 0)
                    percept = Double.parseDouble(line);
                else{
                    weightsList.add(Double.parseDouble(line));
                }
                j++;
         }
        double[] weights = new double[weightsList.size()];
        for(int k=0;k<weightsList.size();k++){
                weights[k] = weightsList.get(k);
         }
            model[i] = new SVMModel(weights, percept);
            weightsList.clear();
}

注意weightsList.clear();