hive GenericUDF1

 和UDF相比，通用GDF（GenericUDF）支持复杂类型（比如List，struct等）的输入和输出。

           下面来看一个小示例。

            Hive中whereme表中包含若干人的行程如下：  

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  1. A       2013-10-10 8:00:00      home  
  2. A       2013-10-10 10:00:00     Super Market  
  3. A       2013-10-10 12:00:00     KFC  
  4. A       2013-10-10 15:00:00     school  
  5. A       2013-10-10 20:00:00     home  
  6. A       2013-10-15 8:00:00      home  
  7. A       2013-10-15 10:00:00     park  
  8. A       2013-10-15 12:00:00     home  
  9. A       2013-10-15 15:30:00     bank  
  10. A       2013-10-15 19:00:00     home  

           通过查询我们要得到如下结果：  

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  1. A   2013-10-10  08:00:00    home    10:00:00    Super Market  
  2. A   2013-10-10  10:00:00    Super Market    12:00:00    KFC  
  3. A   2013-10-10  12:00:00    KFC 15:00:00    school  
  4. A   2013-10-10  15:00:00    school  20:00:00    home  
  5. A   2013-10-15  08:00:00    home    10:00:00    park  
  6. A   2013-10-15  10:00:00    park    12:00:00    home  
  7. A   2013-10-15  12:00:00    home    15:30:00    bank  
  8. A   2013-10-15  15:30:00    bank    19:00:00    home  

           1.编写GenericUDF. 

[java] view plain copy
 
  1. package com.wz.udf;  
  2. import org.apache.hadoop.io.Text;  
  3. import org.apache.hadoop.io.LongWritable;  
  4. import org.apache.hadoop.io.IntWritable;  
  5. import org.apache.hadoop.io.FloatWritable;  
  6. import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;  
  7. import org.apache.hadoop.hive.ql.exec.UDFArgumentException;  
  8. import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;  
  9. import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;  
  10. import org.apache.hadoop.hive.ql.metadata.HiveException;  
  11. import org.apache.hadoop.hive.serde2.lazy.LazyString;  
  12. import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;  
  13. import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;  
  14. import org.apache.hadoop.hive.serde2.objectinspector.ListObjectInspector;  
  15. import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;  
  16. import org.apache.hadoop.hive.serde2.objectinspector.StandardListObjectInspector;  
  17. import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;  
  18. import org.apache.hadoop.hive.serde2.objectinspector.StructField;  
  19. import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;  
  20. import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;  
  21. import org.apache.hadoop.hive.serde2.objectinspector.primitive.LongObjectInspector;  
  22. import org.apache.hadoop.hive.serde2.objectinspector.primitive.IntObjectInspector;  
  23. import org.apache.hadoop.hive.serde2.objectinspector.primitive.FloatObjectInspector;  
  24. import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;  
  25. import java.text.DateFormat;  
  26. import java.text.SimpleDateFormat;  
  27. import java.util.Date;   
  28. import java.util.Calendar;  
  29. import java.util.ArrayList;  
  30.    
  31. public class helloGenericUDF extends GenericUDF {  
  32.      ////输入变量定义  
  33.      private ObjectInspector peopleObj;  
  34.      private ObjectInspector timeObj;  
  35.      private ObjectInspector placeObj;  
  36.      //之前记录保存  
  37.      String strPreTime = "";  
  38.      String strPrePlace = "";   
  39.      String strPrePeople = "";  
  40.    
  41.      @Override  
  42.      //1.确认输入类型是否正确  
  43.      //2.输出类型的定义  
  44.      public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {  
  45.           peopleObj = (ObjectInspector)arguments[0];  
  46.           timeObj = (ObjectInspector)arguments[1];  
  47.           placeObj = (ObjectInspector)arguments[2];  
  48.           //输出结构体定义  
  49.           ArrayList structFieldNames = new ArrayList();  
  50.           ArrayList structFieldObjectInspectors = new ArrayList();  
  51.           structFieldNames.add("people");  
  52.       structFieldNames.add("day");  
  53.           structFieldNames.add("from_time");  
  54.           structFieldNames.add("from_place");  
  55.           structFieldNames.add("to_time");  
  56.           structFieldNames.add("to_place");  
  57.    
  58.           structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  59.           structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  60.           structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  61.           structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  62.       structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  63.       structFieldObjectInspectors.add( PrimitiveObjectInspectorFactory.writableStringObjectInspector );  
  64.   
  65.           StructObjectInspector si2;  
  66.           si2 = ObjectInspectorFactory.getStandardStructObjectInspector(structFieldNames, structFieldObjectInspectors);   
  67.           return si2;  
  68.      }  
  69.    
  70.      //遍历每条记录  
  71.      @Override  
  72.      public Object evaluate(DeferredObject[] arguments) throws HiveException{  
  73.       LazyString LPeople = (LazyString)(arguments[0].get());  
  74.       String strPeople = ((StringObjectInspector)peopleObj).getPrimitiveJavaObject( LPeople );  
  75.   
  76.       LazyString LTime = (LazyString)(arguments[1].get());  
  77.       String strTime = ((StringObjectInspector)timeObj).getPrimitiveJavaObject( LTime );  
  78.   
  79.       LazyString LPlace = (LazyString)(arguments[2].get());  
  80.       String strPlace = ((StringObjectInspector)placeObj).getPrimitiveJavaObject( LPlace );  
  81.       
  82.       Object[] e;     
  83.       e = new Object[6];  
  84.   
  85.           try  
  86.       {  
  87.                 //如果是同一个人，同一天  
  88.         if(strPrePeople.equals(strPeople) && IsSameDay(strTime) )  
  89.         {  
  90.                 e[0] = new Text(strPeople);  
  91.                         e[1] = new Text(GetYearMonthDay(strTime));  
  92.                 e[2] = new Text(GetTime(strPreTime));  
  93.                 e[3] = new Text(strPrePlace);  
  94.                 e[4] = new Text(GetTime(strTime));  
  95.                 e[5] = new Text(strPlace);  
  96.         }  
  97.                 else  
  98.                 {  
  99.                 e[0] = new Text(strPeople);  
  100.             e[1] = new Text(GetYearMonthDay(strTime));  
  101.                 e[2] = new Text("null");  
  102.                 e[3] = new Text("null");  
  103.                 e[4] = new Text(GetTime(strTime));  
  104.                 e[5] = new Text(strPlace);  
  105.                 }  
  106.           }  
  107.           catch(java.text.ParseException ex)  
  108.           {  
  109.           }  
  110.              
  111.       strPrePeople = new String(strPeople);  
  112.       strPreTime= new String(strTime);  
  113.       strPrePlace = new String(strPlace);  
  114.   
  115.           return e;  
  116.      }  
  117.    
  118.      @Override  
  119.      public String getDisplayString(String[] children) {  
  120.           assert( children.length>0 );  
  121.    
  122.           StringBuilder sb = new StringBuilder();  
  123.           sb.append("helloGenericUDF(");  
  124.           sb.append(children[0]);  
  125.           sb.append(")");  
  126.    
  127.           return sb.toString();  
  128.      }  
  129.   
  130.      //比较相邻两个时间段是否在同一天  
  131.      private boolean IsSameDay(String strTime) throws java.text.ParseException{     
  132.      if(strPreTime.isEmpty()){  
  133.          return false;  
  134.          }  
  135.          String curDay = GetYearMonthDay(strTime);  
  136.          String preDay = GetYearMonthDay(strPreTime);  
  137.      return curDay.equals(preDay);  
  138.      }  
  139.   
  140.      //获取年月日  
  141.      private String GetYearMonthDay(String strTime)  throws java.text.ParseException{  
  142.          DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
  143.          Date curDate = df.parse(strTime);  
  144.      df = new SimpleDateFormat("yyyy-MM-dd");  
  145.          return df.format(curDate);  
  146.      }  
  147.   
  148.      //获取时间  
  149.      private String GetTime(String strTime)  throws java.text.ParseException{  
  150.          DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
  151.          Date curDate = df.parse(strTime);  
  152.          df = new SimpleDateFormat("HH:mm:ss");  
  153.          return df.format(curDate);  
  154.      }  
  155. }  

           2.在Hive里面创建两张表，一张包含结构体的表保存执行GenericUDF查询后的结果，另外一张用于保存最终结果.

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  1. hive> create table whereresult(people string,day string,from_time string,from_place string,to_time string,to_place string);  
  2. OK  
  3. Time taken: 0.287 seconds  
  4. hive> create table tmpResult(info struct<people:string,day:string,from_time:str>ing,from_place:string,to_time:string,to_place:string>);  
  5. OK  
  6. Time taken: 0.074 seconds  

           3.执行GenericUDF查询,得到最终结果。  

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    1. hive> insert overwrite table tmpResult select hellogenericudf(whereme.people,whereme.time,whereme.place) from whereme;  
    2. hive> insert overwrite table whereresult select info.people,info.day,info.from_time,info.from_place,info.to_time,info.to_place from tmpResult where info.from_time<>'null';  
    3. Total MapReduce jobs = 2  
    4. Launching Job 1 out of 2  
    5. Number of reduce tasks is set to 0 since there's no reduce operator  
    6. Starting Job = job_201312022129_0006, Tracking URL = http://localhost:50030/jobdetails.jsp?jobid=job_201312022129_0006  
    7. Kill Command = /home/wangzhun/hadoop/hadoop-0.20.2/bin/../bin/hadoop job  -Dmapred.job.tracker=localhost:9001 -kill job_201312022129_0006  
    8. Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0  
    9. 2013-12-02 22:48:40,733 Stage-1 map = 0%,  reduce = 0%  
    10. 2013-12-02 22:48:49,825 Stage-1 map = 100%,  reduce = 0%  
    11. 2013-12-02 22:48:52,869 Stage-1 map = 100%,  reduce = 100%  
    12. Ended Job = job_201312022129_0006  
    13. Ended Job = -383357832, job is filtered out (removed at runtime).  
    14. Moving data to: hdfs://localhost:9000/tmp/hive-root/hive_2013-12-02_22-48-24_406_2701579121398466034/-ext-10000  
    15. Loading data to table default.whereresult  
    16. Deleted hdfs://localhost:9000/user/hive/warehouse/whereresult  
    17. Table default.whereresult stats: [num_partitions: 0, num_files: 1, num_rows: 0, total_size: 346, raw_data_size: 0]  
    18. 8 Rows loaded to whereresult  
    19. MapReduce Jobs Launched:   
    20. Job 0: Map: 1   HDFS Read: 420 HDFS Write: 346 SUCESS  
    21. Total MapReduce CPU Time Spent: 0 msec  
    22. OK  
    23. Time taken: 29.098 seconds  
    24. hive> select * from whereresult;  
    25. OK  
    26. A   2013-10-10  08:00:00    home    10:00:00    Super Market  
    27. A   2013-10-10  10:00:00    Super Market    12:00:00    KFC  
    28. A   2013-10-10  12:00:00    KFC 15:00:00    school  
    29. A   2013-10-10  15:00:00    school  20:00:00    home  
    30. A   2013-10-15  08:00:00    home    10:00:00    park  
    31. A   2013-10-15  10:00:00    park    12:00:00    home  
    32. A   2013-10-15  12:00:00    home    15:30:00    bank  
    33. A   2013-10-15  15:30:00    bank    19:00:00    home  
    34. Time taken: 0.105 seconds  
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原文地址：https://www.cnblogs.com/cxhfuujust/p/7553002.html