Question

我正在尝试使用Hadoop-LZO包（使用步骤here构建）。似乎一切顺利，因为我能够将我的lzo文件转换为索引文件（这会按预期返回big_file.lzo.index）：

hadoop jar /path/to/your/hadoop-lzo.jar com.hadoop.compression.lzo.LzoIndexer big_file.lzo

然后我在mapreduce作业中使用这些文件（以big_file.lzo.index作为输入）：

import com.hadoop.mapreduce.LzoTextInputFormat;
....
Job jobConverter = new Job(conf, "conversion");
jobConverter.setJar("JsonConverter.jar");
jobConverter.setInputFormatClass(LzoTextInputFormat.class);
....

我收到以下错误：

Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected
    at com.hadoop.mapreduce.LzoTextInputFormat.listStatus(LzoTextInputFormat.java:62)
    at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.getSplits(FileInputFormat.java:389)
    at com.hadoop.mapreduce.LzoTextInputFormat.getSplits(LzoTextInputFormat.java:101)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:304)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:321)
    at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:199)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1290)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1287)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1595)
    at org.apache.hadoop.mapreduce.Job.submit(Job.java:1287)
    at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1308)
    at org.wwbp.JsonConverter.run(JsonConverter.java:116)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.wwbp.JsonConverter.main(JsonConverter.java:74)
    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)

我已经看到其他问题回答这个问题，他们说要重新构建Hadoop v2。所以我从Github重新下载了所有内容并运行

% hadoop version
Hadoop 2.7.0-mapr-1607
Compiled by root on 2016-07-18T07:56Z
Compiled with protoc 2.5.0
This command was run using /opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/common/hadoop-common-2.7.0-mapr-1607.jar

% ant clean compile-native tar -Dhadoopversion=27
....
tar:
  [tar] Building tar: ../jars/hadoop-lzo/build/hadoop-lzo-0.4.15.tar.gz

BUILD SUCCESSFUL
Total time: 15 seconds

构建路径时如下：

C_INCLUDE_PATH=../jars/lzo-2.09/include
LIBRARY_PATH=../jars/lzo-2.09/lib
JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64

我真的不确定我做错了什么。如何让ant看到Hadoop v2？

编辑1 ：可能需要注意：当我同时运行mapreduce作业（调用LzoTextInputFormat.class）和lzo转换器（在big_file.lzo上）时，我的类路径如下< / p>

CLASS_PATH=/opt/mapr/hadoop/hadoop-2.7.0/etc/hadoop:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/common/lib/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/common/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/hdfs:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/hdfs/lib/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/hdfs/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/yarn/lib/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/yarn/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/mapreduce/lib/*:/opt/mapr/hadoop/hadoop-2.7.0/share/hadoop/mapreduce/*:/contrib/capacity-scheduler/*.jar:/opt/mapr/lib/kvstore*.jar:/opt/mapr/lib/libprotodefs*.jar:/opt/mapr/lib/baseutils*.jar:/opt/mapr/lib/maprutil*.jar:/opt/mapr/lib/json-20080701.jar:/opt/mapr/lib/flexjson-2.1.jar:/jars/hadoop-lzo-0.4.15/hadoop-lzo-0.4.15.jar

编辑2 ：如果我按如下方式索引lzo文件（即尝试使用DistributedLzoIndexer而不是LzoIndexer通过mapreduce作业进行索引），我收到类似的错误：

> hadoop jar /path/to/your/hadoop-lzo.jar com.hadoop.compression.lzo.DistributedLzoIndexer big_file.lzo
16/12/09 13:06:24 INFO mapreduce.Job:  map 0% reduce 0%
16/12/09 13:06:29 INFO mapreduce.Job: Task Id : attempt_1472572940387_0370_m_000000_0, Status : FAILED
Error: Found interface org.apache.hadoop.mapreduce.TaskAttemptContext, but class was expected

Answer 1

不知道上面为什么不起作用所以我从头开始使用这个回购：

https://github.com/twitter/hadoop-lzo

而不是上面链接的那个，并使用maven来构建而不是ant（使用与上面相同的所有设置）。

Java Hadoop-lzo找到了接口，但是类是LzoTextInputFormat

1 个答案: