Eclipse远程调试Hadoop接续上篇

       上次遇到了几个问题接着又遇到了几个问题：简单记录下来，方便以后参考：

（1）关于权限的问题 关闭权限设置

<property>
        <name>dfs.permissions</name>
        <value>false</value>
        <description>
            If "true", enable permission checking in HDFS.
            If "false", permission checking is turned off,
            but all other behavior is unchanged.
            Switching from one parameter value to the other does not change the mode,
            o</description>
    </property>

（2）Job Tracker is not yet Running 

查看日志可以看到错误信息，一般通过重新更改tmp.dir和重新format可以解决

（3）配置问题：

 

参数设置保持：hadoop.tmp.dir 与core-site.xml中一致

（4）调试的使用我指定hadoop的jar文件 把 lib下，hadoop-1.2.1下jar文件jar加入编译环境

（5 ）最后的WordCount.java

 import java.io.IOException;

 import java.util.StringTokenizer;
 
 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.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();
    conf.set("mapred.job.tracker", "172.16.89.85:9001"); //好像是权限问题
    conf.set("mapred.jar", "D:\\software\\hadoop-1.2.1\\wordcount.jar"); //导出项目为jar包
    String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
    if (otherArgs.length != 2) {
      System.err.println("Usage: wordcount <in> <out>");
      System.exit(2);
    }
    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]));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}

添加了红色的2行。。。

（6）运行时候指定的input :hdfs://172.16.89.85:9000/input  hdfs://172.16.89.85:9000/outputbu

 （7）上张成果图，勉励自己及没成功的少年们。。。

        

  通过网页：http://172.16.89.85:50070 浏览HDFS文件可以看到

   

总结一下：

   不同的人可能开发环境也好，设置，环境也好，遇到问题多看日志信息、多尝试，心里淡定下来。。我遇到的问题有时候真要调试半天。。

不过总告诉自己一定有办法的,办法总比困难多。问题总会解决的！