hadoopstreaming如何实现多路输出扩展
这篇文章主要介绍hadoop streaming如何实现多路输出扩展,文中介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们一定要看完!
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PrefixMultipleOutputFormat 实现的功能点有两个
按照key的前缀输入到不同的目录
删除最终输出结果中的tab
##使用方式### ####按照key 的 前缀输出到不同目录中
$maserati_hadoop jar $HADOOP_HOME/share/hadoop/tools/lib/hadoop-streaming-2.6.0.jar -libjars ./adts.jar -D mapred.job.name=$name \ -D mapred.reduce.tasks=5 \ -inputformat org.apache.hadoop.mapred.TextInputFormat \ -outputformat com.sogou.adt.adts.PrefixMultipleOutputFormat \ -input $input \ -output $output \ -mapper ./m_mapper.sh \ -reducer ./m_reducer.sh \ -file m_mapper.sh \ -file m_reducer.sh
其中outputformat
指定的是 自己时间的类 -libjars ./adts.jar
导入的是自己的jar包
###mapper 和 reduer.sh ##m_maper.sh## #!/bin/bash awk -F " " '{ for(i=1;i<=NF;i++) print $i; }' ###m_reduer.sh### #!/bin/bash awk -F "\t" '{ if(NR%3==0) print "A#"$1; if(NR%3==1) print "B#"$1; if(NR%3==2) print "C#"$1; }'
这样就可以将数字分别输入到不同的路径中了
####删除行尾的tab 只需要加入com.sogou.adt.adts.ignoreseparator=true
指定忽略行尾的tab 即可
$maserati_hadoop jar $HADOOP_HOME/share/hadoop/tools/lib/hadoop-streaming-2.6.0.jar -libjars ./adts.jar -D mapred.job.name=$name \ -D mapred.reduce.tasks=5 \ -D com.sogou.adt.adts.ignoreseparator=true \ -inputformat org.apache.hadoop.mapred.TextInputFormat \ -outputformat com.sogou.adt.adts.PrefixMultipleOutputFormat \ -input $input \ -output $output \ -mapper ./m_mapper.sh \ -reducer ./m_reducer.sh \ -file m_mapper.sh \ -file m_reducer.sh
###PrefixMultipleOutputFormat的实现方式 由于并不熟悉java语言,在大学学的那点java也早就还给老师了^v^ 搭建编译环境费了些时日,不过好在有个现成的eclipse java 环境 还有两年前搭建好的hadoop环境(它稍微修复一点点就ok了, 能跑程序了, 真是万幸)。
###我的环境
eclipse
jdk1.6.0
jar包
hadoop-common-2.6.0.jar
hadoop-mapreduce-client-core-2.6.0.jar
这个简单介绍一下 编译之前我还在担心hadoop streaming 依赖的jar包哪里去找,用不用自己编译(hadoop所有的源码编译让人有点头疼),后来发现jar 包都可以在 hadoop 运行环境中找到,瞬间释然了。
###源码 这段代码挺好理解的了一个LineRecordWriter类 (大部分都是从现有的TextOutputFormat 类中扒的 只是改动一点 读配置 关闭输出tab) generateFileNameForKeyValue
实现了从前缀读取并输出到不同的目录中,代码一目了然
package com.sogou.adt.adts; import java.io.DataOutputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.compress.CompressionCodec; import org.apache.hadoop.io.compress.GzipCodec; import org.apache.hadoop.mapred.FileOutputFormat; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.RecordWriter; import org.apache.hadoop.mapred.Reporter; import org.apache.hadoop.mapred.lib.MultipleTextOutputFormat; import org.apache.hadoop.util.Progressable; import org.apache.hadoop.util.ReflectionUtils; public class PrefixMultipleOutputFormat extends MultipleTextOutputFormat{ [@Override](https://my.oschina.net/u/1162528) protected Text generateActualKey(Text key, Text value) { // TODO Auto-generated method stub return super.generateActualKey(key, value); } protected static class LineRecordWriter implements RecordWriter { private static final String utf8 = "UTF-8"; private static final byte[] newline; static { try { newline = "\n".getBytes(utf8); } catch (UnsupportedEncodingException uee) { throw new IllegalArgumentException("can't find " + utf8 + " encoding"); } } protected DataOutputStream out; private final byte[] keyValueSeparator; public LineRecordWriter(DataOutputStream out, String keyValueSeparator) { this.out = out; try { this.keyValueSeparator = keyValueSeparator.getBytes(utf8); } catch (UnsupportedEncodingException uee) { throw new IllegalArgumentException("can't find " + utf8 + " encoding"); } } public LineRecordWriter(DataOutputStream out) { this(out, "\t"); } /** * Write the object to the byte stream, handling Text as a special * case. * [@param](https://my.oschina.net/u/2303379) o the object to print * [@throws](https://my.oschina.net/throws) IOException if the write throws, we pass it on */ private void writeObject(Object o) throws IOException { if (o instanceof Text) { Text to = (Text) o; out.write(to.getBytes(), 0, to.getLength()); } else { out.write(o.toString().getBytes(utf8)); } } public synchronized void write(K key, V value) throws IOException { boolean nullKey = key == null || key instanceof NullWritable; boolean nullValue = value == null || value instanceof NullWritable; if (nullKey && nullValue) { return; } if (!nullKey) { writeObject(key); } if (!(nullKey || nullValue)) { out.write(keyValueSeparator); } if (!nullValue) { writeObject(value); } out.write(newline); } public synchronized void close(Reporter reporter) throws IOException { out.close(); } } [@Override](https://my.oschina.net/u/1162528) protected RecordWriter getBaseRecordWriter(FileSystem fs, JobConf job, String name, Progressable arg3) throws IOException { boolean isCompressed = getCompressOutput(job); String keyValueSeparator = job.get("mapreduce.output.textoutputformat.separator", "\t"); Boolean ignoreseparator = job.getBoolean("com.sogou.adt.adts.ignoreseparator", false); if(ignoreseparator) { keyValueSeparator=""; } if (!isCompressed) { Path file = FileOutputFormat.getTaskOutputPath(job, name); fs = file.getFileSystem(job); FSDataOutputStream fileOut = fs.create(file, arg3); return new LineRecordWriter (fileOut, keyValueSeparator); } else { Class extends CompressionCodec> codecClass = getOutputCompressorClass(job, GzipCodec.class); // create the named codec CompressionCodec codec = ReflectionUtils.newInstance(codecClass, job); // build the filename including the extension Path file = FileOutputFormat.getTaskOutputPath(job, name + codec.getDefaultExtension()); fs = file.getFileSystem(job); FSDataOutputStream fileOut = fs.create(file, arg3); return new LineRecordWriter (new DataOutputStream (codec.createOutputStream(fileOut)), keyValueSeparator); } } [@Override](https://my.oschina.net/u/1162528) protected String generateFileNameForKeyValue(Text key, Text value, String name) { int keyLength = key.getLength(); String outputName = name; if(keyLength < 2) return outputName; Text sep = new Text(); sep.append(key.getBytes(), 1, 1); if(sep.find("#") != -1) { Text newFlag = new Text(); newFlag.append(key.getBytes(), 0, 1); String flag = newFlag.toString(); //outputName = name+"-"+flag; outputName = flag+"/"+name+"-"+flag; Text newValue = new Text(); newValue.append(key.getBytes(), 2, keyLength-2); key.set(newValue); } System.out.printf("[shishuai]System[key [%s]][value:[%s]] output[%s]\n",key.toString(),value.toString(),outputName); return outputName; }
}
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