Question

我正在使用ELasticsearch 5.4和Hadoop 2.7.3，并希望将数据从HDFS写入Elasticsearch.My数据在blog.json中：

{"id":"1","title":"git简介","posttime":"2016-06-11","content":"svn与git的最主要区别..."}
{"id":"2","title":"ava中泛型的介绍与简单使用","posttime":"2016-06-12","content":"基本操作：CRUD ..."}
{"id":"3","title":"SQL基本操作","posttime":"2016-06-13","content":"svn与git的最主要区别..."}
{"id":"4","title":"Hibernate框架基础","posttime":"2016-06-14","content":"Hibernate框架基础..."}
{"id":"5","title":"Shell基本知识","posttime":"2016-06-15","content":"Shell是什么..."}

我把blog.json放到了HDFS：

hadoop fs -put blog.json /work

然后我启动Elasticsearch 5.4并编写我的java代码：

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.elasticsearch.hadoop.mr.EsOutputFormat;

import java.io.IOException;

/**
 * Created by bee on 4/1/17.
 */
public class HdfsToES {

    public static class MyMapper extends Mapper<Object, Text, NullWritable,
            BytesWritable> {

        public void map(Object key, Text value, Mapper<Object, Text,
                NullWritable, BytesWritable>.Context context) throws IOException, InterruptedException {
            byte[] line = value.toString().trim().getBytes();
            BytesWritable blog = new BytesWritable(line);
            context.write(NullWritable.get(), blog);
        }
    }


    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

        Configuration conf = new Configuration();
        conf.setBoolean("mapred.map.tasks.speculative.execution", false);
        conf.setBoolean("mapred.reduce.tasks.speculative.execution", false);
        conf.set("es.nodes", "localhost:9200/");
        conf.set("es.resource", "blog/csdn");
        conf.set("es.mapping.id", "id");
        conf.set("es.input.json", "yes");

        Job job = Job.getInstance(conf, "hadoop es write test");
        job.setMapperClass(HdfsToES.MyMapper.class);
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(EsOutputFormat.class);

        job.setMapOutputKeyClass(NullWritable.class);
        job.setMapOutputValueClass(BytesWritable.class);

        // 设置输入路径
        FileInputFormat.setInputPaths(job, new Path
                ("hdfs://localhost:9000//work/blog.json"));

        job.waitForCompletion(true);
    }
}

我在Elasticsearch中没有任何数据的空索引流动异常：

java.lang.Exception: org.elasticsearch.hadoop.serialization.EsHadoopSerializationException: org.codehaus.jackson.JsonParseException: Unexpected character ('b' (code 98)): expected a valid value (number, String, array, object, 'true', 'false' or 'null')
 at [Source: [B@5cdff749; line: 1, column: 3]

它适用于Elasticsearch 2.3不能5.4。如何更新我的代码？

Answer 1

public static class MyMapper extends Mapper<Object, Text, NullWritable,
        BytesWritable> {

    public void map(Object key, Text value, Mapper<Object, Text,
            NullWritable, BytesWritable>.Context context) throws IOException, InterruptedException {
        byte[] line = value.toString().trim().getBytes();
        BytesWritable blog = new BytesWritable(line);
        context.write(NullWritable.get(), blog);
    }
}

Answer 2

public static class someMapper extends Mapper<Object, Text, NullWritable, Text>
job.setMapOutputValueClass(Text.class);

不要将byteswritable用于mapvalue，而只需使用text。它适用于我的elasticsearch6.1.1，hadoop 2.7.3

将数据写入Elasticsearch：EsHadoopSerializationException

2 个答案: