Question

给定以这种方式构建的数据集，我正在尝试解决任务要获取的mapreduce问题：节点x节点y

  2         4
  3         1
  .         .
  .         .

只有与x存在（x，y）的y

输出应该类似于：

2
3

问题是，当我尝试执行应用程序时，出现此错误：

biar@pfp-VirtualBox:~$ yarn jar /home/biar/Desktop/examgraph.jar ExamGraph 3 12
Exception in thread "main" java.lang.NoSuchMethodException: ExamGraph.main([Ljava.lang.String;)
    at java.lang.Class.getMethod(Class.java:1678)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:215)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)

这是我的应用程序的代码：

public class ExamGraph {

  public static class TokenizeMapper extends Mapper<LongWritable , Text, Text, Text>{

    public void map(LongWritable key, Text value, Context context
                    ) throws IOException, InterruptedException {
      int[] a = new int[2];
      value = new Text(value.toString());
      String[] coppia = value.toString().split(" ");
      a[0] = Integer.parseInt(coppia[0]);
      a[1] = Integer.parseInt(coppia[1]);
      if (a[1] > a[0]) context.write(new Text(coppia[1]), new Text("SI,0"));
      else context.write(new Text(coppia[1]), new Text("NO,0"));

      String[] coppiaInv = value.toString().split(" ");
      a[0] = Integer.parseInt(coppiaInv[1]);
      a[1] = Integer.parseInt(coppiaInv[0]);
      if (a[0] < a[1]) context.write(new Text(coppiaInv[0]), new Text("SI,1"));
      else context.write(new Text(coppiaInv[0]), new Text("NO,1"));
    }
  }

  public static class IntSumReducer
       extends Reducer<Text,Text,Text,NullWritable> {


    public void reduce(Text key, Iterable<Text> values,
                       Context context
                       ) throws IOException, InterruptedException {
      boolean evenResult = false;
      boolean oddResult = false;
      for (Text value : values) {
        String[] valori = value.toString().split(",");
        int a;
        a = Integer.parseInt(valori[1]);
        if (valori[0].equals("SI") && a == 0) evenResult = true;
        if (valori[0].equals("SI") && a == 1) oddResult = true;
      }

      if (evenResult == true && oddResult == true) {
          context.write(key, NullWritable.get());
      }
      else context.write(new Text("Not valid"), NullWritable.get());

    }
  }

  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    Job job = Job.getInstance(conf, "ExamGraph");
    job.setJarByClass(ExamGraph.class);
    job.setMapperClass(TokenizeMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(NullWritable.class);
    FileInputFormat.addInputPath(job, new Path(args[0]));
    FileOutputFormat.setOutputPath(job, new Path(args[1]));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}

我认为问题出在主代码中，但我看不出它在哪里。有人提示吗？

MapReduce应用程序-线程“主”中的异常java.lang.NoSuchMethodException

0 个答案: