Hive之UDF创建永久函数

具体步骤:

1、JAVA代码:

package com.bigdata;
import org.apache.hadoop.hive.ql.exec.UDF;

public class Add extends UDF {
	
	public Integer evaluate(Integer a, Integer b) {
		if (null == a || null == b) {
			return null;
		}
		return a + b;
	}

	public Double evaluate(Double a, Double b) {
		if (a == null || b == null) {
			return null;
		}
		return a + b;
	}

	public Integer evaluate(Integer... a) {
		int total = 0;
		for (int i = 0; i < a.length; i++) {
			if (a[i] != null) {
				total += a[i];
			}
		}
		return total;
	}
	
}
2、将JAVA类打jar包并上传至hdfs中。

3、进入hive,执行命令CREATE FUNCTION default.add AS 'com.bigdata.Add' USING JAR 'hdfs://service/add.jar'; 

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