Pig错误：无法找到或加载主类org.apache.pig.Main

May 发表于 Dev

可能

我是PIG的初学者。

我在WIKI之后编写了一个程序，将文件中的单词转换为大写。

--cat UPPER.java

package com.bigdata.myUdf;

import java.io.IOException;
import org.apache.pig.EvalFunc;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.util.WrappedIOException;

public class UPPER extends EvalFunc<String> {

public String exec(Tuple input) throws IOException {
    if (input == null || input.size() == 0)
    return null;
    try{
    String str = (String)input.get(0);
    return str.toUpperCase();
    }catch(Exception e){
    throw WrappedIOException.wrap("Caught exception processing input row ", e);
    }
    }

}

-猫/home/hduser/lab/mydata/myscript.pig

REGISTER /home/hduser/software/myUdfs/UPPER.jar
std_det = LOAD '/pigdata/udf1.txt' USING PigStorage(',') as (name:chararray);
B = FOREACH std_det GENERATE com.bigdata.myUdf.UPPER(name);
dump B;

但是，当我运行它时，我得到了错误。

 java -cp com.bigdata.myUdf.UPPER.jar org.apache.pig.Main -x local /home/hduser/lab/mydata/myscript.pig

错误

Error: Could not find or load main class org.apache.pig.Main

猫.bashrc

export PIG_INSTALL=/home/hduser/software/pig
export PATH="${PATH}:${PIG_INSTALL}/bin"
export PIG_CLASSPATH=$HADOOP_CONF_DIR:${PIG_INSTALL}:.
export CLASSPATH=.:${PIG_CLASSPATH}

猪脚本位于：/home/hduser/lab/mydata/myscript.pig

该JAR文件位于：/home/hduser/software/myUdfs/UPPER.jar

请帮助我了解我在做什么错。提前致谢。在遵循Shivashakti的指示之后。该程序已运行，但未提供任何输出。

 pig -x local myScript.pig

 15/01/05 04:47:57 INFO pig.ExecTypeProvider: Trying ExecType : LOCAL
15/01/05 04:47:57 INFO pig.ExecTypeProvider: Picked LOCAL as the ExecType
2015-01-05 04:47:57,920 [main] INFO  org.apache.pig.Main - Apache Pig version 0.14.0 (r1640057) compiled Nov 16 2014, 18:02:05
2015-01-05 04:47:57,921 [main] INFO  org.apache.pig.Main - Logging error messages to:       /home/hduser/lab/piglog/pig_1420462077918.log
2015-01-05 04:47:57,959 [main] INFO  org.apache.hadoop.conf.Configuration.deprecation - user.name is deprecated. Instead, use mapreduce.job.user.name
2015-01-05 04:47:58,314 [main] INFO  org.apache.hadoop.conf.Configuration.deprecation - fs.default.name is deprecated. Instead, use fs.defaultFS
2015-01-05 04:47:58,315 [main] INFO  org.apache.hadoop.conf.Configuration.deprecation - mapred.job.tracker is deprecated. Instead, use mapreduce.jobtracker.address
2015-01-05 04:47:58,318 [main] INFO  org.apache.pig.backend.hadoop.executionengine.HExecutionEngine - Connecting to hadoop file system at:   file:///
2015-01-05 04:47:58,463 [main] INFO  org.apache.hadoop.conf.Configuration.deprecation -   fs.default.name is deprecated. Instead, use fs.defaultFS
2015-01-05 04:47:59,070 [main] INFO  org.apache.hadoop.conf.Configuration.deprecation - fs.default.name is deprecated. Instead, use fs.defaultFS
2015-01-05 04:47:59,227 [main] INFO  org.apache.pig.Main - Pig script completed in 2 seconds and 505 milliseconds (2505 ms)

锡瓦萨克（Sivasakthi jayaraman）

您可以按照以下步骤进行吗？

1.从以下链接下载3个jar文件（pig-0.11.1.jar，hadoop-common-0.21.0.jar和piggybank.jar）

http://www.java2s.com/Code/Jar/p/Downloadpig0111jar.htm
http://www.java2s.com/Code/Jar/h/Downloadhadoopcommon0210jar.htm
http://www.java2s.com/Code/Jar/p/Downloadpiggybankjar.htm

2.将上述3个jar文件全部设置为您的类路径

export CLASSPATH=/tmp/pig-0.11.1.jar:/tmp/hadoop-common-0.21.0.jar:/tmp/piggybank.jar

3.从当前目录创建目录名称“ com / bigdata / myUdf /”

>>mkdir -p com/bigdata/myUdf/

4.编译UPPER.java文件，并确保正确设置JAVA_HOME，并且上述所有三个jar文件都包含在类路径中，否则将出现编译问题

>>javac UPPER.java

5.将已编译的UPPER.class文件移至“ com / bigdata / myUdf /”文件夹

>>mv UPPER.class com/bigdata/myUdf/

6.创建一个jar文件名UPPER.jar

>>jar -cvf UPPER.jar com/

7.现在将UPPER.jar包含在您的Pig脚本中，并运行以下命令

   >>pig -x local myscript.pig

一旦运行了上面的命令，您将获得实际的输出。

输入示例

hello
world

myscript.pig

REGISTER UPPER.jar; 
std_det = LOAD 'input' USING PigStorage(',') as (name:chararray);
B = FOREACH std_det GENERATE com.bigdata.myUdf.UPPER(name);
dump B;

输出：

(HELLO)
(WORLD)

示例命令：

$ ls
UPPER.java      input   myscript.pig

$ mkdir -p com/bigdata/myUdf/
$ javac UPPER.java
$ mv UPPER.class com/bigdata/myUdf/
$ jar -cvf UPPER.jar com/
$ pig -x local myscript.pig

本文收集自互联网，转载请注明来源。

如有侵权，请联系[email protected] 删除。