hive的自定义函数.

ToLowerCase的例子

把单词转化为小写的Demo.

添加maven依赖

写自定义函数可能只需要hive-exec包即可

 <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.zb</groupId>
    <artifactId>hive-udf</artifactId>
    <version>1.0</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.apache.hive/hive-common -->
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-common</artifactId>
            <version>2.1.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.hive/hive-exec -->
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-exec</artifactId>
            <version>2.1.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/junit/junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.mockito/mockito-core -->
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>2.10.0</version>
            <scope>test</scope>
        </dependency>


    </dependencies>


</project>

编写一个类继承UDF

package cn.zb.udf;

import org.apache.hadoop.hive.ql.exec.UDF;

/**
 * Created by v_zhangbing on 2017/10/11.
 */
public class ToLowerCase extends UDF {
}