Presto自定义函数-Toy模板网

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1、引入所需pom

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.test.czj</groupId>
    <artifactId>presto</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>7</source>
                    <target>7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <configuration>
                    <createDependencyReducedPom>false</createDependencyReducedPom>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <artifactSet>
                                <includes>
                                    <include>com.yahoo.datasketches:memory</include>
                                    <include>com.yahoo.datasketches:sketches-core</include>
                                    <include>com.google.guava:guava</include>
                                </includes>
                            </artifactSet>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
    <name>presto</name>
    <description>presto</description>
    <dependencies>
        <dependency>
            <groupId>com.facebook.presto</groupId>
            <artifactId>presto-spi</artifactId>
            <version>0.281</version>
        </dependency>
        <dependency>
            <groupId>com.facebook.presto</groupId>
            <artifactId>presto-array</artifactId>
            <version>0.264</version>
        </dependency>
        <dependency>
            <groupId>com.google.gdata</groupId>
            <artifactId>core</artifactId>
            <version>1.47.1</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>com.yahoo.datasketches</groupId>
            <artifactId>sketches-core</artifactId>
            <version>0.13.0</version>
        </dependency>
    </dependencies>

</project>

2、添加resources

创建目录META-INF/services

创建文件 com.facebook.presto.spi.Plugin，指明你所实现的Plugin位置文章来源地址https://www.toymoban.com/news/detail-535491.html

com.test.presto.function.InstallPlugin

3、函数的实现

import com.facebook.presto.common.type.StandardTypes;
import com.facebook.presto.spi.function.Description;
import com.facebook.presto.spi.function.ScalarFunction;
import com.facebook.presto.spi.function.SqlType;
import com.yahoo.memory.Memory;
import com.yahoo.sketches.tuple.DoubleSummary;
import com.yahoo.sketches.tuple.DoubleSummaryDeserializer;
import com.yahoo.sketches.tuple.Sketch;
import com.yahoo.sketches.tuple.Sketches;
import io.airlift.slice.Slice;
/**
将byte[]的sketch转换成double类型
*/
public class SketchFunciton {

    @ScalarFunction("sketch_estimate")
    @Description("hive sketch to double function")
    @SqlType(StandardTypes.DOUBLE)
    public static double sketch_estimate(@SqlType(StandardTypes.VARBINARY) Slice input) {
        try {
            Sketch<DoubleSummary> sketch = Sketches.heapifySketch(
                    Memory.wrap(input.byteArray()),
                    new DoubleSummaryDeserializer()
            );
            return sketch.getEstimate();
        } catch (Exception e) {
            e.printStackTrace();
            return -1d;
        }
    }
}

实现Plugin接口

import com.facebook.presto.spi.Plugin;
import com.google.common.collect.ImmutableSet;

import java.util.Set;


public class InsightPlugin implements Plugin {
    @Override
    public Set<Class<?>> getFunctions()
    {
        return ImmutableSet.<Class<?>>builder()
                .add(SketchFunciton.class)
                .build();
    }
}