Hadoop基础教程-第12章 Hive：进阶（12.2 自定义函数）（草稿）

<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.hadron</groupId>
    <artifactId>hiveFun</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>hiveFun</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </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>

        <dependency>
            <groupId>jdk.tools</groupId>
            <artifactId>jdk.tools</artifactId>
            <version>1.8</version>
            <scope>system</scope>
            <systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>
        </dependency>
    </dependencies>
    <repositories>
    <repository>
      <id>central</id>
      <name>Central Repository</name>
      <url>http://maven.aliyun.com/nexus/content/repositories/central</url>
      <layout>default</layout>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>
  </repositories>
</project>

package cn.hadron.hiveFun;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.DoubleWritable;

public class LevelUDF extends UDF{

     public Text evaluate(double sal){

         if(sal<1500){
             return new Text("穷人");
         }else if(sal<2000){
             return new Text("温饱");
         }else if(sal<3000){
             return new Text("低产");
         }else if(sal<6000){
             return new Text("中产");
         }else if(sal<8000){
             return new Text("高产");
         }else{
             return new Text("富人");
         }
     }
}

hive> add jar /root/hiveFun.jar;
Added [/root/hiveFun.jar] to class path
Added resources: [/root/hiveFun.jar]
hive> create temporary function level_sal as 'cn.hadron.hiveFun.LevelUDF';
OK
Time taken: 1.06 seconds
hive>

hive> select ename,level_sal(sal) from emp;
OK
CLARK   低产
KING    中产
MILLER  穷人
SMITH   穷人
JONES   低产
FORD    中产
ALLEN   温饱
WARD    穷人
MARTIN  穷人
BLAKE   低产
TURNER  温饱
JAMES   穷人
HADRON  高产
Time taken: 0.181 seconds, Fetched: 13 row(s)
hive>