Changes between Version 1 and Version 2 of waue/2010/0115-HelloHadoopV2

Timestamp:

Jan 20, 2010, 9:27:21 PM (14 years ago)

Author:

waue

Comment:

--

waue/2010/0115-HelloHadoopV2

@@ -1 +1 @@
  = Hello Hadoop V2  =
 
+
+ * hellohadoop v2 main
 {{{
 #!java
@@ -72 +74 @@
 
 }}}
+
+ * mapper
+
+{{{
+#!java
+import java.io.IOException;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.Mapper;
+
+public class HelloMapperV2 extends Mapper<LongWritable, Text, Text, Text> {
+
+        public void map(LongWritable key, Text value, Context context)
+                        throws IOException, InterruptedException {
+                context.write(new Text(key.toString()), value);
+        }
+
+}
+
+}}}
+
+ * reducer
+
+{{{
+#!java
+import java.io.IOException;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.Reducer;
+
+public class HelloReducerV2 extends Reducer<Text, Text, Text, Text> {
+        public void reduce(Text key, Iterable<Text> values, Context context)
+                        throws IOException, InterruptedException {
+
+                String str = new String("");
+                Text final_key = new Text();
+                Text final_value = new Text();
+                // 將key值相同的values，透過 && 符號分隔之
+                for (Text tmp : values) {
+                        str += tmp.toString() + " &&";
+                }
+
+                final_key.set(key);
+                final_value.set(str);
+
+                context.write(final_key, final_value);
+        }
+}
+}}}