Question

 public static void main(String[] args) throws Exception 
 {
    Configuration conf = new Configuration();
    conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/core-site.xml"));
    conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/hdfs-site.xml"));
    Job job = new Job();
    //job.setJarByClass(WordCount.class);
    job.setJobName("WordCounter");

    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("/home/pramukh/eclipse/eclipseproj/hadoop/input/input.txt"));
    FileOutputFormat.setOutputPath(job, new Path("/home/pramukh/eclipse/eclipseproj/hadoop/output.txt"));
//System.exit(0);
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }

这是我的java hadoop wordcount示例，它给出了以下错误：

线程“main”中的异常java.lang.NoClassDefFoundError： java.lang.Class.forName0上的org / apache / avro / io / DatumReader（Native 方法）在java.lang.Class.forName（Class.java:348）at org.apache.hadoop.conf.Configuration.getClassByName（Configuration.java:1074）在 org.apache.hadoop.io.serializer.SerializationFactory.add（SerializationFactory.java:69）在 org.apache.hadoop.io.serializer.SerializationFactory。（SerializationFactory.java:62）在 org.apache.hadoop.mapreduce.split.JobSplitWriter.writeNewSplits（JobSplitWriter.java:117）在 org.apache.hadoop.mapreduce.split.JobSplitWriter.createSplitFiles（JobSplitWriter.java:74）在 org.apache.hadoop.mapred.JobClient.writeNewSplits（JobClient.java:1030）在 org.apache.hadoop.mapred.JobClient.writeSplits（JobClient.java:1041）在org.apache.hadoop.mapred.JobClient.access $ 700（JobClient.java:179）在org.apache.hadoop.mapred.JobClient $ 2.run（JobClient.java:959）at org.apache.hadoop.mapred.JobClient $ 2.run（JobClient.java:912）at java.security.AccessController.doPrivileged（Native Method）at javax.security.auth.Subject.doAs（Subject.java:422）at org.apache.hadoop.security.UserGroupInformation.doAs（UserGroupInformation.java:742）在 org.apache.hadoop.mapred.JobClient.submitJobInternal（JobClient.java:912）在org.apache.hadoop.mapreduce.Job.submit（Job.java:500）at org.apache.hadoop.mapreduce.Job.waitForCompletion（Job.java:530）at at hadoop.WordCount.main（WordCount.java:66）引起：java.lang.ClassNotFoundException：org.apache.avro.io.DatumReader at at java.net.URLClassLoader.findClass（URLClassLoader.java:381）at java.lang.ClassLoader.loadClass（ClassLoader.java:424）at sun.misc.Launcher $ AppClassLoader.loadClass（Launcher.java:331）at at java.lang.ClassLoader.loadClass（ClassLoader.java:357）

提前致谢。

Answer 1

如果此程序中的其余代码已更正; 我建议你检查路径 OutputPath文件夹不存在我尝试过你的代码更改文件路径，代码可以正常运行

FileInputFormat.addInputPath(job, new Path("hdfs://localhost:9000/wordcount/test.txt"));
    FileOutputFormat.setOutputPath(job, new Path("hdfs://localhost:9000/wordcount/out"));

hadoop ERROR ON WORDCOUNT PROGRAM

1 个答案: