猪UDF在Java中：错误---错误1066：无法打开迭代器的别名

问题描述：

我是新来的猪我输入的数据是猪UDF在Java中：错误---错误1066：无法打开迭代器的别名

（消息，NIL，2015-07-01,22： 58：53.66，E，machine.com.name，12,0xd6，字符串，字符串，0,0.0，键=值&键= 123456789 &键=值&键= US &键=公司&键=消息&关键= 123456789 & key = String & key = String & Key = String & Key = String）

我写的Java UDF如下

package com.pig.udf; 

import java.io.IOException; 
import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.HashMap; 
import java.util.Map; 

import org.apache.pig.EvalFunc; 
import org.apache.pig.data.Tuple; 

public class PigUDF extends EvalFunc<Map> { 


    @Override 
    public Map<String, String> exec(Tuple input) throws IOException { 
     // If tuple is null, has fewer than 3 values, or has an even number of 
     // values 
     if (input == null || input.size() < 3 || (input.size() % 2 == 0)) { 
      throw new IOException("Incorrect number of values."); 
     } 

     String source = (String) input.get(0); 
     System.out.println("input Source"+source); 
     String delim = (input.size() > 1) ? (String) input.get(1) : "&"; 
     int length = (input.size() > 2) ? (Integer) input.get(2) : 0; 
     if (source == null || delim == null) { 
      return null; 
     } 

     String[] splits = source.split(delim, length); 
     System.out.println("Splits"+ splits); 
     ArrayList<String> arrayList = new ArrayList<String>(
       Arrays.asList(splits)); 
     Map<String, String> map = new HashMap<String, String>(); 
     for (String keyValue : arrayList) { 
      int end = keyValue.indexOf('='); 
      if (end != -1) { 
       map.put(keyValue.substring(0, end), keyValue.substring(end + 1)); 
      } 

     } 
     System.out.println("map"+map); 

     return map; 

    } 

}

当我与上面的Java UDF我收到以下错误运行我的猪脚本解析输入数据的最后一个字符串

Pig Stack Trace 
--------------- 
ERROR 1066: Unable to open iterator for alias C 

org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1066: Unable to open iterator for alias C 
    at org.apache.pig.PigServer.openIterator(PigServer.java:892) 
    at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:774) 
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:372) 
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:198) 
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:173) 
    at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:84) 
    at org.apache.pig.Main.run(Main.java:607) 
    at org.apache.pig.Main.main(Main.java:156) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:606) 
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221) 
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136) 
Caused by: java.io.IOException: Job terminated with anomalous status FAILED 
    at org.apache.pig.PigServer.openIterator(PigServer.java:884) 
    ... 13 more 



    Application Log 
    ------------------------------------------------------------------- 
    Application application_1436453941326_0020 failed 2 times due to AM Container for appattempt_1436453941326_0020_000002 exited with exitCode: 1 
For more detailed output, check application tracking page:http://quickstart.cloudera:8088/proxy/application_1436453941326_0020/Then, click on links to logs of each attempt. 
Diagnostics: Exception from container-launch. 
Container id: container_1436453941326_0020_02_000001 
Exit code: 1 
Stack trace: ExitCodeException exitCode=1: 
at org.apache.hadoop.util.Shell.runCommand(Shell.java:538) 
at org.apache.hadoop.util.Shell.run(Shell.java:455) 
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:715) 
at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:211) 
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:302) 
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:82) 
at java.util.concurrent.FutureTask.run(FutureTask.java:262) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
at java.lang.Thread.run(Thread.java:745) 
Container exited with a non-zero exit code 1 
Failing this attempt. Failing the application.

我的脚本运行良好，没有Java UDF功能，也给我outfile。当我在我的Pig脚本中包含Java UDF时，就会出现这个问题。有运行猪任何指针我的Java UDF和机器之间没有Java版本不匹配可以理解

猪脚本：

Register '/home/cloudera/Pig/PigUDF_1.7.jar'; 
Register '/home/cloudera/Pig/pig.jar'; 
A= Load 'Logs_message.txt' using PigStorage(',') as (component:chararray,Nil:chararray,date:chararray,time:chararray,E:chararray,machine_address:chararray,number1:chararray,hex_number:chararray,cal_type:chararray,cal_name:chararray,number2:chararray,number3:chararray,data:chararray) 
B = filter A by cal_name matches 'CHANGEDMESSAGE'; 
C = foreach B generate cal_name ,com.pig.udf.PigUDF(data) as dataMap; 
dump C ;

你是怎么称呼udf的？另外，请查找更详细的日志。 – Frederic

您可以将猪脚本粘贴到您要调用UDF的地方，我认为它是您猪脚本中的问题 – Abhi

Hi @Fred，我在哪里可以找到更详细的日志？ – Divya

答

我看到3个问题与您的代码：

你在第一行中错过了一个分号。不知道它是如何运行的，假设这是将它复制到StackOverflow的错误
您将变量“E”命名为：这是一个保留变量。不知道这会有什么影响，但我不会这样做是安全的。请参阅here获取Pig关键字列表
（这可能是导致错误的原因）。您的验证没有意义。它看起来像你创建了一个分割函数，用来设置3个或更少的参数（要分割的字符串，分隔符和最大分割大小）。但是，您正在验证输入的参数超过3个。你也正在验证它有偶数个参数。这看起来像是一个验证，旨在为之后的字符串，而不是之前。

应该是这样的：

if (input == null || input.size() == 0 || input.size() > 3) { throw new IOException("Incorrect number of values."); } //... if(splits.length % 2 != 0) throw new IOException("Invalid key value pairs");

我建议，直到你已经调试它们不运行在Hadoop上云中的程序，让他们先在本地工作。如果使用PigServer类，则可以通过eclipse或其他IDE在开发计算机上调试UDF。

猪UDF在Java中：错误---错误1066：无法打开迭代器的别名

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