MM2.java 文件源码

@Override
protected void reduce(LongWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException {

    int k = context.getConfiguration().getInt("k", -1);

    double[] result = new double[k];

    for (Text value : values) {
        String[] ai = value.toString().split(",");
        for (int j = 0; j < k; j++) {
            result[j] += Double.parseDouble(ai[j]);
        }
    }

    StringBuilder res = new StringBuilder(prefix);

    for (int i = 0; i < k; i++) {
        res.append(result[i]);
        if (i < k - 1) {
            res.append(",");
        }
    }
    context.write(key, new Text(res.toString()));
}