Use mapreduce eclipse plugin

Source: Internet
Author: User

The local environment is as follows:

Eclipse 3.6

Hadoop-0.20.2

Hive-0.5.0-dev

1. Install plug-ins for hadoop-0.20.2-eclipse-plugin. Note: The/hadoop-0.20.2/contrib/eclipse-plugin/hadoop-0.20.2-eclipse-plugin.jar in the hadoop directory has a problem in eclipse3.6 and cannot run on hadoop server, can be downloaded from http://code.google.com/p/hadoop-eclipse-plugin/

2. Select the MAP/reduce view: window-> open pers...-> other...-> MAP/reduce

3. Add DFS locations: click map/reduce locations-> New hadoop loaction, and fill in the corresponding host and Port

12345678910
MAP/reduce master: Host: 10.10.xx.xx port: 9001 DFS master: Host: 10.10.xx.xx (Select User M/R master host) Port: 9000 User name: Root to change hadoop in advance parameters. job. ugi. The default value is drwho and TARDIS. Change it to root and TARDIS. If no options are displayed, use eclipse-clean to restart eclipse. Otherwise, the org. Apache. hadoop. Security. accesscontrolexception error may be reported.

4. Set the host of the local machine:

12345
10.10.xx.xx ZW-hadoop-master. ZW-hadoop-master # Note that there must be a ZW-hadoop-master later ., otherwise, an error occurs when running MAP/reduce: Java. lang. illegalargumentexception: Wrong FS: HDFS: // ZW-hadoop-MASTER: 9000/user/root/oplog/out/_ temporary/_ partition, expected: HDFS: // ZW-hadoop-master. 9000 at Org. apache. hadoop. FS. filesystem. checkpath (filesystem. java: 352)

5. Create a map/reduce project and create Mapper, CER, and driver classes. Note that the automatically generated code is based on the old version of hadoop and you can modify it yourself:

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081
package com.sohu.hadoop.test;    import java.util.StringTokenizer;   import org.apache.hadoop.io.IntWritable;   import org.apache.hadoop.io.Text;   import org.apache.hadoop.mapreduce.Mapper;    public class MapperTest extends Mapper<Object, Text, Text, IntWritable> {       private final static IntWritable one = new IntWritable(1);        public void map(Object key, Text value, Context context)               throws IOException, InterruptedException {           String userid = value.toString().split("[|]")[2];           context.write(new Text(userid), new IntWritable(1));       }   }     package com.sohu.hadoop.test;    import java.io.IOException;   import org.apache.hadoop.io.IntWritable;   import org.apache.hadoop.io.Text;   import org.apache.hadoop.mapreduce.Reducer;    public class ReducerTest extends Reducer<Text, IntWritable, Text, IntWritable> {        private IntWritable result = new IntWritable();        public void reduce(Text key, Iterable<IntWritable> values, Context context)               throws IOException, InterruptedException {           int sum = 0;           for (IntWritable val : values) {               sum += val.get();           }           result.set(sum);           context.write(key, result);       }   }     package com.sohu.hadoop.test;    import org.apache.hadoop.conf.Configuration;   import org.apache.hadoop.fs.Path;   import org.apache.hadoop.io.IntWritable;   import org.apache.hadoop.io.Text;   import org.apache.hadoop.io.compress.CompressionCodec;   import org.apache.hadoop.io.compress.GzipCodec;   import org.apache.hadoop.mapreduce.Job;   import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;   import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;   import org.apache.hadoop.util.GenericOptionsParser;    public class DriverTest {       public static void main(String[] args) throws Exception {           Configuration conf = new Configuration();           String[] otherArgs = new GenericOptionsParser(conf, args)                   .getRemainingArgs();           if (otherArgs.length != 2)            {               System.err.println("Usage: DriverTest <in> <out>");               System.exit(2);           }           Job job = new Job(conf, "Driver Test");           job.setJarByClass(DriverTest.class);           job.setMapperClass(MapperTest.class);           job.setCombinerClass(ReducerTest.class);           job.setReducerClass(ReducerTest.class);           job.setOutputKeyClass(Text.class);           job.setOutputValueClass(IntWritable.class);            conf.setBoolean("mapred.output.compress", true);           conf.setClass("mapred.output.compression.codec", GzipCodec.class,CompressionCodec.class);            FileInputFormat.addInputPath(job, new Path(otherArgs[0]));           FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));            System.exit(job.waitForCompletion(true) ? 0 : 1);       }   }

6. On drivertest, click Run as-> run on hadoop and select the corresponding hadoop locaion.

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.