Changes between Initial Version and Version 1 of waue/helloHadoop

Timestamp:

Dec 17, 2011, 12:37:32 PM (12 years ago)

Author:

waue

Comment:

--

waue/helloHadoop

@@ +1 @@
+{{{
+#!java
+
+import java.io.IOException;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.Text;
+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 HelloHadoop {
+
+  static public class HelloMapper extends
+      Mapper<LongWritable, Text, LongWritable, Text> {
+
+    public void map(LongWritable key, Text value, Context context)
+        throws IOException, InterruptedException {
+      // 將出入資料 原封不動的寫入 輸出
+      context.write((LongWritable) key, (Text) value);
+    }
+
+  }
+
+  static public class HelloReducer extends
+      Reducer<LongWritable, Text, LongWritable, Text> {
+    public void reduce(LongWritable key, Iterable<Text> values,
+        Context context) throws IOException, InterruptedException {
+      Text val = new Text();
+      // 取回 val 的資料
+      for (Text str : values) {
+        val.set(str.toString());
+      }
+      // 將取回的資料引入輸出
+      context.write(key, val);
+    }
+  }
+
+  public static void main(String[] args) throws IOException,
+      InterruptedException, ClassNotFoundException {
+    // 引入 $HADOOP_HOME/conf 內控制檔內的資料
+    Configuration conf = new Configuration();
+    // 宣告job 取得conf 並設定名稱 Hadoop Hello World
+    Job job = new Job(conf, "Hadoop Hello World");
+    // 設定此運算的主程式
+    job.setJarByClass(HelloHadoop.class);
+    // 設定輸入路徑
+    FileInputFormat.setInputPaths(job, "/user/hadoop/input");
+    // 設定輸出路徑
+    FileOutputFormat.setOutputPath(job, new Path("/user/hadoop/output-hh1"));
+    // 指定定map class
+    job.setMapperClass(HelloMapper.class);
+    // 指定reduce class
+    job.setReducerClass(HelloReducer.class);
+    // 開使運算
+    job.waitForCompletion(true);
+
+  }
+}
+
+}}}