public class Average implements CombinerAggregator<Number> {

int count = 0;
double sum = 0;

@Override
public Double init(final TridentTuple tuple) {
    this.count++;
    if (!(tuple.getValue(0) instanceof Double)) {

        double d = ((Number) tuple.getValue(0)).doubleValue();

        this.sum += d;

        return d;
    }

    this.sum += (Double) tuple.getValue(0);
    return (Double) tuple.getValue(0);

}

@Override
public Double combine(final Number val1, final Number val2) {
    return this.sum / this.count;

}

@Override
public Double zero() {
    this.sum = 0;
    this.count = 0;
    return 0D;
}
}

我是一个完全的新手，当谈到三叉戟以及，所以我不完全是如果以下将工作。但它可能：

public class AvgAgg extends BaseAggregator<AvgState> {
    static class AvgState {
        long count = 0;
        long total = 0;

        double getAverage() {
            return total/count;
        }
    }

    public AvgState init(Object batchId, TridentCollector collector) {
        return new AvgState();
    }

    public void aggregate(AvgState state, TridentTuple tuple, TridentCollector collector) {
        state.count++;
        state.total++;
    }

    public void complete(AvgState state, TridentCollector collector) {
        collector.emit(new Values(state.getAverage()));
    }
}