UDF精简使用大全

一、UDF的分类

UDF类型

描述

UDF(User Defined Scalar Function)

用户自定义标量值函数。其输入与输出是一对一的关系,即读入一行数据,输出一个值。

UDTF(User Defined Table Valued Function)

自定义表值函数。用于解决调用一次函数输出多行数据的需求。UDTF是唯一能够返回多个字段的自定义函数。UDTF不等于UDT(User Defined Type)。

UDAF(User Defined Aggregation Function)

自定义聚合函数。其输入与输出是多对一的关系,即将多条输入记录聚合成一个输出值。UDAF可以与SQL中的GROUP BY语句联用。具体语法请参见

聚合函数

二、UDF参数解析

MaxCompute数据类型与Java数据类型的对应关系如下。

注意点:

  • 此处ARRAY类型对应的Java类型是List,而不是数组。
  • VARCHAR,BINART,STRUCT一些数据类型是ODPS独有的
  • Java中对应的数据类型以及返回值数据类型是对象,数据类型首字母需大写。

MaxCompute Type

Java Type

TINYINT

java.lang.Byte

SMALLINT

java.lang.Short

INT

java.lang.Integer

BIGINT

java.lang.Long

FLOAT

java.lang.Float

DOUBLE

java.lang.Double

DECIMAL

java.math.BigDecimal

BOOLEAN

java.lang.Boolean

STRING

java.lang.String

VARCHAR

com.aliyun.odps.data.Varchar

BINARY

com.aliyun.odps.data.Binary

DATETIME

java.util.Date

TIMESTAMP

java.sql.Timestamp

ARRAY

java.util.List

MAP

java.util.Map

STRUCT

com.aliyun.odps.data.Struct

MaxCompute 2.0版本支持定义Java UDF时,使用Writable类型作为参数和返回值。MaxCompute数据类型和Java Writable类型的映射关系如下。

MaxCompute Type

Java Writable Type

TINYINT

ByteWritable

SMALLINT

ShortWritable

INT

IntWritable

BIGINT

LongWritable

FLOAT

FloatWritable

DOUBLE

DoubleWritable

DECIMAL

BigDecimalWritable

BOOLEAN

BooleanWritable

STRING

Text

VARCHAR

VarcharWritable

BINARY

BytesWritable

DATETIME

DatetimeWritable

TIMESTAMP

TimestampWritable

INTERVAL_YEAR_MONTH

IntervalYearMonthWritable

INTERVAL_DAY_TIME

IntervalDayTimeWritable

ARRAY

N/A

MAP

N/A

STRUCT

N/A

MaxCompute SQL Type

Python 2 Type

BIGINT

INT

STRING

STR

DOUBLE

FLOAT

BOOLEAN

BOOL

DATETIME

INT

FLOAT

FLOAT

CHAR

STR

VARCHAR

STR

BINARY

BYTEARRAY

DATE

INT

DECIMAL

DECIMAL.DECIMAL

ARRAY

LIST

MAP

DICT

STRUCT

COLLECTIONS.NAMEDTUPLE

MaxCompute SQL Type

Python 3 Type

BIGINT

INT

STRING

UNICODE

DOUBLE

FLOAT

BOOLEAN

BOOL

DATETIME

DATETIME.DATETIME

FLOAT

FLOAT

CHAR

UNICODE

VARCHAR

UNICODE

BINARY

BYTES

DATE

DATETIME.DATE

DECIMAL

DECIMAL.DECIMAL

ARRAY

LIST

MAP

DICT

STRUCT

COLLECTIONS.NAMEDTUPLE

三、UDF的使用方式

UDF、UDTF、UDAT可进行参考文档

https://help.aliyun.com/document_detail/27867.html?spm=a2c4g.11186623.6.762.463d7468xnFPHb

JAVA UDF

UDF的高级使用:

3.1UDF中的变长参数

java语言:

package com.mrtest.cn;
import com.aliyun.odps.udf.UDF;
import com.aliyun.odps.udf.annotation.Resolve;
import java.util.ArrayList;
import java.util.List;
@Resolve({"*->array"})
public class TestUDF extends UDF {
    public List evaluate(String ... s) {
        List list = new ArrayList();
        for (String name : s) {
            list.add(name);
        }
        return list;
    }
}

Python语言:

from odps.udf import annotate
@annotate("*->bigint")
class ParamFunc(object):
   def evaluate(self, *nums):
        sum = 0
        for num in nums:
            sum=num+sum
        return sum

3.2UDF的重载

注意事项:对于List与List是不能解析对应的方法的,这种属于类型擦除

package com.aliyun.odps.examples.udf;
import com.aliyun.odps.udf.UDF;
public class UDFExample extends UDF {
  public String evaluate(String a) {
    return "s2s:" + a;
  }
  public String evaluate(String a, String b) {
    return "ss2s:" + a + "," + b;
  }
  public String evaluate(String a, String b, String c) {
    return "sss2s:" + a + "," + b + "," + c;
  }
}

3.3UDF访问对应文件和表

java语言:

package com.aliyun.odps.examples.udf;
import com.aliyun.odps.udf.ExecutionContext;
import com.aliyun.odps.udf.UDF;
import com.aliyun.odps.udf.UDFException;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Iterator;
public class UDFResource extends UDF {
  ExecutionContext ctx;
  long fileResourceLineCount;
  long tableResource1RecordCount;
  long tableResource2RecordCount;
  @Override
  public void setup(ExecutionContext ctx) throws UDFException {
    this.ctx = ctx;
    try {
      InputStream in = ctx.readResourceFileAsStream("file_resource.txt");
      BufferedReader br = new BufferedReader(new InputStreamReader(in));
      String line;
      fileResourceLineCount = 0;
      while ((line = br.readLine()) != null) {
        fileResourceLineCount++;
      }
      br.close();
      Iterator iterator = ctx.readResourceTable("table_resource1").iterator();
      tableResource1RecordCount = 0;
      while (iterator.hasNext()) {
        tableResource1RecordCount++;
        iterator.next();
      }
      iterator = ctx.readResourceTable("table_resource2").iterator();
      tableResource2RecordCount = 0;
      while (iterator.hasNext()) {
        tableResource2RecordCount++;
        iterator.next();
      }
    } catch (IOException e) {
      throw new UDFException(e);
    }
  }
  /**
   * project: example_project table: wc_in2 partitions: p2=1,p1=2 columns: colc,colb
   */
  public String evaluate(String a, String b) {
    return "ss2s:" + a + "," + b + "|fileResourceLineCount=" + fileResourceLineCount
        + "|tableResource1RecordCount=" + tableResource1RecordCount + "|tableResource2RecordCount="
        + tableResource2RecordCount;
  }
}



python语言:

#coding: utf-8
from odps.udf import annotate
from odps.distcache import get_cache_file
@annotate('double -> double')
class Compute(object):
    def __init__(self):
            import json
            #获取对应文本文件
            cache_file = get_cache_file('file.txt')
            dataMat = []
            for line in cache_file :
                curLine = line.strip().split(',')
                #处理逻辑
            cache_file.close()
            #获取对应的表文件
            records = list(get_cache_table('table_resource1'))
         for record in records:
             self.my_dict[record[0]] = [record[1]]
                #处理逻辑
    def evaluate(self, input):
        #处理逻辑

      

3.4UDF访问外部网络(VPC、外部网络、专有网络)

https://help.aliyun.com/document_detail/187866.html

3.5UDF使用第三方包

https://help.aliyun.com/document_detail/189752.html

#coding: utf-8
# explode.py
from odps.udf import annotate
from odps.distcache import get_cache_archive
import datetime
def include_package_path(res_name):
    import os, sys
    archive_files = get_cache_archive(res_name)
    dir_names = sorted ([os.path.dirname(os.path.normpath(f.name)) for f in archive_files 
                        if '.dist_info' not in f.name], key=lambda v: len(v))
    sys.path.append(os.path.dirname(dir_names[0]))
@annotate("string->boolean")
class is_workday_udf(object):
    def __init__(self):
        include_package_path('chinese-calendar-master.zip')
    def evaluate(self, date_str):
        # try:
        import chinese_calendar
        date_strs = date_str.split("-")
        year_num = int(date_strs[0])
        month_num = int(date_strs[1])
        day_num = int(date_strs[2])
        date_num = datetime.date(year=year_num, month=month_num, day=day_num)
        result = chinese_calendar.is_workday(date_num)
        return result
        # except:
        #     return True

函数的注册

UDF精简使用大全

执行的select的的操作

set odsp.pypy.enabled=false;
set odps.isolation.session.enable=true;
select my_json('{"info":"11","desc":"a|b","filename":"4b-2a-3c-4d-5b"}') as a;



3.6使用嵌入式开发UDF

java语言:

CREATE TEMPORARY FUNCTION foo AS 'com.mypackage.Reverse' USING
#CODE ('lang'='JAVA')
package com.mypackage;
import com.aliyun.odps.udf.UDF;
public class Reverse extends UDF {
  public String evaluate(String input) {
    if (input == null) return null;
    StringBuilder ret = new StringBuilder();
    for (int i = input.toCharArray().length - 1; i >= 0; i--) {
      ret.append(input.toCharArray()[i]);
    }
    return ret.toString();
  }
}
#END CODE;


SELECT foo('abdc');

  • 嵌入式代码块可以置于USING后或脚本末尾,置于USING后的代码块作用域仅为CREATE TEMPORARY FUNCTION语句。
  • CREATE TEMPORARY FUNCTION创建的函数为临时函数,仅在本次执行生效,不会存入MaxCompute的Meta系统。


python语言:

CREATE TEMPORARY FUNCTION foo AS 'embedded.UDFTest' USING
#CODE ('lang'='PYTHON', 'filename'='embedded')
from odps.udf import annotate
@annotate("bigint->bigint")
class UDFTest(object):
  def evaluate(self, a):
    return a * a
#END CODE;


SELECT foo(4);

  • Python代码的缩进需要符合Python语言规范。
  • 由于注册Python UDF时AS后的类名需要包含Python源码的文件名,您可以通过’filename’=’embedded’指定一个虚拟文件名。

3.7使用SQL语言定义函数

create sql function my_sum(@a BIGINT, @b BIGINT, @c BIGINT) returns @my_sum BIGINT
as begin 
    @temp := @a + @b;
    @my_sum := @temp + @c;
end;
create sql function my_func(@s STRING)
AS if(@s rlike '"git_(m|a)"', 1, 0);


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UDF精简使用大全

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