Question

我正在尝试从hbase表中读取数据，对其进行一些处理，然后使用以下代码将其存储在另一个表中

package analysis;
import java.io.IOException;
import org.apache.hadoop.io.Text;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.HBaseConfiguration;

import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableReducer; 
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.util.Bytes;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
public class Author_ref {

public static class MyMapper extends TableMapper<Text,Text>  {

    public void map(ImmutableBytesWritable row, Result value,Context context)throws IOException, InterruptedException
    {
        String key = new String(row.get());
        String values = new String(value.getValue(Bytes.toBytes("authors"), Bytes.toBytes("authors")));
        String clean_values = values.replaceAll("[","");
        String clean_values2 = clean_values.replaceAll("]","");
        String authors[] = clean_values2.trim().split(",");

        for (String author : authors)
        {
            //Put row = new Put();
            context.write(new Text(author),new Text( key));
        }

    }
}

public static class MyReducer extends TableReducer<Text, Text, ImmutableBytesWritable>
{
    public void reduce(Text author, Iterable<Text> values,Context context)throws IOException,InterruptedException
    {
        String papers = "";
        for (Text x : values)
        {
            papers = papers + ","+x.toString();
        }
        Put p = new Put(author.getBytes());
        p.add(Bytes.toBytes("papers_writen"),Bytes.toBytes("papers_writen"),Bytes.toBytes(papers));
        context.write(null, p);
    }
}
public static void main(String[] args) throws Exception
{
Configuration config = HBaseConfiguration.create();
Job job = new Job(config,"ExampleSummary");
Scan scan = new Scan();
scan.setCaching(500);        // 1 is the default in Scan, which will be bad for MapReduce jobs
scan.setCacheBlocks(false);
job.setJarByClass(Author_ref.class);     // class that contains mapper and reducer
TableMapReduceUtil.initTableMapperJob(
        "Dataset",        // input table
        scan,               // Scan instance to control CF and attribute selection
        MyMapper.class,     // mapper class
        Text.class,         // mapper output key
        Text.class,  // mapper output value
        job);
TableMapReduceUtil.initTableReducerJob(
        "Author_paper",        // output table
        MyReducer.class,    // reducer class
        job);

job.setNumReduceTasks(1);   // at least one, adjust as required

System.exit(job.waitForCompletion(true)?0:1);

}

}

我遇到了以下错误。

线程“主”中的异常java.lang.NoSuchMethodError：org.apache.hadoop.yarn.api.records.URL.fromURI（Ljava / net / URI;）Lorg / apache / hadoop / yarn / api / records /网址；在org.apache.hadoop.mapreduce.v2.util.LocalResourceBuilder.createLocalResources（LocalResourceBuilder.java:144）在org.apache.hadoop.mapreduce.v2.util.MRApps.setupDistributedCache（MRApps.java:531）在org.apache.hadoop.mapred.LocalDistributedCacheManager.setup（LocalDistributedCacheManager.java:92）在org.apache.hadoop.mapred.LocalJobRunner $ Job。（LocalJobRunner.java:171）在org.apache.hadoop.mapred.LocalJobRunner.submitJob（LocalJobRunner.java:760）在org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal（JobSubmitter.java:253）在org.apache.hadoop.mapreduce.Job $ 11.run（Job.java:1570）在org.apache.hadoop.mapreduce.Job $ 11.run（Job.java:1567）在java.security.AccessController.doPrivileged（本机方法）在javax.security.auth.Subject.doAs（Subject.java:422）在org.apache.hadoop.security.UserGroupInformation.doAs（UserGroupInformation.java:1889）在org.apache.hadoop.mapreduce.Job.submit（Job.java:1567）在org.apache.hadoop.mapreduce.Job.waitForCompletion（Job.java:1588）在analysis.Author_ref.main（Author_ref.java:111）

我正在使用hadoop 2.9和hbase 1.2.6.1

Answer 1

hadoop 2.9和hbase 1.2.x不兼容，请看一下

http://hbase.apache.org/book.html#basic.prerequisites

您将必须使用兼容的版本。

NoSuchMethodException org.apache.hadoop.yarn.api.records.URL.fromURI

1 个答案: