我正在阅读和实施这个教程。最后实现了mapper、reducer和driver三个类。我复制了网页上给出的三个类的代码。但接下来的两个错误没有发生away:-
Map类
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
public class WordCountMapper extends MapReduceBase // Here WordCountMapper was underlined as error source by Eclipse
implements Mapper<LongWritable, Text, Text, IntWritable> {
private final IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(WritableComparable key, Writable value,
OutputCollector output, Reporter reporter) throws IOException {
String line = value.toString();
StringTokenizer itr = new StringTokenizer(line.toLowerCase());
while(itr.hasMoreTokens()) {
word.set(itr.nextToken());
output.collect(word, one);
}
}
}
错误是:
类型wordcountmapper必须实现继承的抽象方法mapper.map(longwritable、text、outputcollector、reporter)
驱动程序类(wordcount.java)
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
public class WordCount {
public static void main(String[] args) {
JobClient client = new JobClient();
JobConf conf = new JobConf(WordCount.class);
// specify output types
conf.setOutputKeyClass(Text.class);
conf.setOutputValueClass(IntWritable.class);
// specify input and output dirs
FileInputPath.addInputPath(conf, new Path("input")); //////////FileInputPath was underlined
FileOutputPath.addOutputPath(conf, new Path("output")); ////////FileOutputPath as underlined
// specify a mapper
conf.setMapperClass(WordCountMapper.class);
// specify a reducer
conf.setReducerClass(WordCountReducer.class);
conf.setCombinerClass(WordCountReducer.class);
client.setConf(conf);
try {
JobClient.runJob(conf);
} catch (Exception e) {
e.printStackTrace();
}
}
}
错误是:
无法解析fileinputpath
无法解析fileoutputpath
1条答案
按热度按时间knpiaxh11#
用这个
而不是这个
在这种情况下,这应该是要导入的