Hadoop1.0 Eclipse Plugin-作业提交

1.环境

     Jdk：1.6.0_10-rc2

     Hadoop：hadoop-1.0.0.tar.gz 

     Eclipse 版本：3.4.0

     Hadoop Eclipse 插件 ：hadoop-eclipse-plugin-1.0.0.jar   下载地址

     操作系统：Windows7 32位 旗舰版

 2.Eclipse插件配置

    2.1   把"hadoop-eclipse-plugin-1.0.0.jar"放到Eclipse的目录的"plugins"中(eclipse/plugins)，重新启动Eclipse生效

    2.2   选择Elipse Window菜单下的"Preference"，配置"Hadoop Map/Reduce"选项，选择Hadoop的安装根目录

     

     2.3 配置Hadoop Location

         在配置Hadoop Location之前 确定hadoop 已启动起来

         Eclipse 切换到“Map/Reduce Locations” 视图 ， 在"Map/Reduce Locations"视图右击 选择"New Hadoop Location"，
        

         * Map/Reduce Master与mapred-site.xml配置文件对应
         * DFS Mast 与core-site.xml配置对应

       创建完成后 ,切换到JavaEE视图    刷新右边的DFS Locations 就会看到dfs文件结构 

     

        可以在节点上右键  创建 删除目录做测试

3.运行wordCount例子程序

  创建一个 Map/Reduce Project项目

 

  创建成功后  WordCount报名对应(源码在hadoop\src\examples\org\apache\hadoop\examples目录下)

 WordCount.java

package org.apache.hadoop.examples;import java.io.IOException;import java.net.URI;import java.util.StringTokenizer;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FSDataInputStream;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.FileUtil;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IOUtils;import org.apache.hadoop.io.IntWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapreduce.Job;import org.apache.hadoop.mapreduce.Mapper;import org.apache.hadoop.mapreduce.Reducer;import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;import org.apache.hadoop.util.GenericOptionsParser;public class WordCount {  public static class TokenizerMapper        extends Mapper<Object, Text, Text, IntWritable>{        private final static IntWritable one = new IntWritable(1);    private Text word = new Text();          public void map(Object key, Text value, Context context                    ) throws IOException, InterruptedException {      StringTokenizer itr = new StringTokenizer(value.toString());      while (itr.hasMoreTokens()) {        word.set(itr.nextToken());        context.write(word, one);      }    }  }    public static class IntSumReducer        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);    }  }  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: wordcount <in> <out>");      System.exit(2);    }    //删除输出目录    FileSystem fileSystem = FileSystem.get(URI.create(args[1]),conf);    fileSystem.delete(new Path("/user/admin/output"), true);        Job job = new Job(conf, "word count");    job.setJarByClass(WordCount.class);    job.setMapperClass(TokenizerMapper.class);    job.setCombinerClass(IntSumReducer.class);    job.setReducerClass(IntSumReducer.class);    job.setOutputKeyClass(Text.class);    job.setOutputValueClass(IntWritable.class);    FileInputFormat.addInputPath(job, new Path(otherArgs[0]));    FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));    boolean flag = job.waitForCompletion(true);    FSDataInputStream  fDataInputStream = null;    try {    fDataInputStream = fileSystem.open(new Path("/user/admin/output/part-r-00000"));    String line = null;    while ((line = fDataInputStream.readLine()) != null) {    System.out.println(line);;}} catch (Exception e) {e.printStackTrace();} finally {IOUtils.closeStream(fDataInputStream);IOUtils.closeStream(fileSystem);}    System.exit( flag ? 0 : 1);  }}

  运行例子

     1.点击WordCount.java，右键-->Run As-->Run Configurations
     2.在弹出的Run Configurations对话框中，点Java Application，右键-->New，这时会新建一个application名为WordCount
     3.配置参数，点Arguments，在Program arguments中配置
        /user/admin/input /user/admin/output
     4.运行时可能会抛出java.lang.OutOfMemoryError: Java heap space异常  配置VM arguments(在Program arguments下)
       -Xms512m -Xmx512m -XX:PermSize=96m

      
     5.右键-->Run on Hadoop        刷新右边的DFS Locations 就会看到结果