生成udaf Java代码

好的，以下是一个简单的UDAF Java代码示例，用于计算输入的整数列表的平均值。

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDAF;
import org.apache.hadoop.hive.ql.exec.UDAFEvaluator;
import org.apache.hadoop.hive.ql.udf.UDFType;

@Description(name = "avg", value = "Calculates the average of a list of integers")
@UDFType(deterministic = true, stateful = false)
public class AvgUDAF extends UDAF {

    public static class AvgUDAFEvaluator implements UDAFEvaluator {

        private int sum = 0;
        private int count = 0;

        public void init() {
            sum = 0;
            count = 0;
        }

        public boolean iterate(int value) {
            if (value != null) {
                sum += value;
                count++;
            }
            return true;
        }

        public Integer terminatePartial() {
            if (count == 0) {
                return null;
            }
            return sum;
        }

        public boolean merge(Integer other) {
            if (other != null) {
                sum += other;
                count++;
            }
            return true;
        }

        public Double terminate() {
            if (count == 0) {
                return null;
            }
            return (double) sum / count;
        }
    }

    public UDAFEvaluator getEvaluator() {
        return new AvgUDAFEvaluator();
    }
}

您可以将此代码复制到您的Java IDE（如Eclipse或IntelliJ IDEA）中，并进行必要的修改，以符合您的UDAF需求。