我的代码是
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
public class word_count_new {
public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
context.write(word, one);
}
}
}
public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {
public void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
context.write(key, new IntWritable(sum));
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = new Job(conf, "wordcount");
// job.setJarByClass(word_count_new.class);
// conf.setJar(word_count_new.jar);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(Map.class);
job.setReducerClass(Reduce.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.setJarByClass(word_count_new.class);
job.waitForCompletion(true);
}
}
下面是类文件和jar：
-rw-r----- 1 ps993w hyhdev 2236 Apr 3 13:56 word_count_new.java
-rw-r----- 1 ps993w hyhdev 1870 Apr 3 13:58 word_count_new$Map.class
-rw-r----- 1 ps993w hyhdev 1638 Apr 3 13:58 word_count_new$Reduce.class
-rw-r----- 1 ps993w hyhdev 1510 Apr 3 13:58 word_count_new.class
-rw-r----- 1 ps993w hyhdev 2990 Apr 3 13:58 word_count_new.jar
错误是
[ps993w@hltd413 ~]$ hadoop jar word_count_new.jar word_count_new /user/ps993w/indata/input_line.dat /user/ps993w/wordcount/
14/04/03 15:53:13 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
14/04/03 15:53:13 WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String).
14/04/03 15:53:13 INFO hdfs.DFSClient: Created HDFS_DELEGATION_TOKEN token 105404 for ps993w on 130.4.240.48:8020
14/04/03 15:53:13 INFO security.TokenCache: Got dt for hdfs://hltd410.hydc.sbc.com:8020/user/ps993w/.staging/job_201402241341_9518;uri=130.4.240.48:8020;t.service=130.4.240.48:8020
14/04/03 15:53:13 INFO input.FileInputFormat: Total input paths to process : 1
14/04/03 15:53:13 INFO lzo.GPLNativeCodeLoader: Loaded native gpl library
14/04/03 15:53:13 INFO lzo.LzoCodec: Successfully loaded & initialized native-lzo library [hadoop-lzo rev cf4e7cbf8ed0f0622504d008101c2729dc0c9ff3]
14/04/03 15:53:13 WARN snappy.LoadSnappy: Snappy native library is available
14/04/03 15:53:13 INFO util.NativeCodeLoader: Loaded the native-hadoop library
14/04/03 15:53:13 INFO snappy.LoadSnappy: Snappy native library loaded
14/04/03 15:53:13 INFO mapred.JobClient: Running job: job_201402241341_9518
14/04/03 15:53:14 INFO mapred.JobClient: map 0% reduce 0%
14/04/03 15:53:24 INFO mapred.JobClient: Task Id : attempt_201402241341_9518_m_000000_0, Status : FAILED
java.lang.RuntimeException: java.lang.ClassNotFoundException: word_count_new$Map
请提出建议
我有同样的问题。问题是hadoop无权读取本地系统上的jar文件。
我从以下位置找到了此解决方案：