Changes between Initial Version and Version 1 of waue/2010/0120

Timestamp:

Jan 22, 2010, 5:23:55 PM (14 years ago)

Author:

shunfa

Comment:

--

waue/2010/0120

@@ +1 @@
+ * 下面程式碼雖然看起來跑wordcount , 但其實跑helloword 
+
+{{{
+#!java
+
+import java.io.IOException;
+import java.util.Iterator;
+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.LongWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapred.OutputCollector;
+import org.apache.hadoop.mapred.Reporter;
+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;
+
+public class wordcount {
+        static public class wcmapper 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,
+                                OutputCollector<Text, IntWritable> output, Reporter reporter)
+                                throws IOException {
+                        String line = value.toString();
+                        StringTokenizer tokenizer = new StringTokenizer(line);
+                        while (tokenizer.hasMoreTokens()) {
+                                word.set(tokenizer.nextToken());
+                                output.collect(word, one);
+                        }
+                }
+        }
+
+        static public class wcreducer extends
+                        Reducer<Text, IntWritable, Text, IntWritable> {
+                public void reduce(Text key, Iterator<IntWritable> values,
+                                OutputCollector<Text, IntWritable> output, Reporter reporter)
+                                throws IOException {
+                        int sum = 0;
+                        while (values.hasNext()) {
+                                sum += values.next().get();
+                        }
+                        output.collect(key, new IntWritable(sum));
+                }
+        }
+
+        public static void main(String[] args) throws Exception {
+
+                Configuration conf = new Configuration();
+
+                Job job = new Job(conf, "wordcount");
+
+                job.setJarByClass(wordcount.class);
+
+                FileInputFormat.setInputPaths(job, "/user/shunfa/input");
+                FileOutputFormat.setOutputPath(job, new Path(
+                                "/user/shunfa/output-wordcount11"));
+
+                job.setMapperClass(wcmapper.class);
+                job.setReducerClass(wcreducer.class);
+                job.waitForCompletion(true);
+        }
+}
+
+}}}
+
+