Changes between Version 2 and Version 3 of waue/2010/0115

Timestamp:

Jan 19, 2010, 5:14:19 PM (14 years ago)

Author:

waue

Comment:

--

waue/2010/0115

@@ -152 +152 @@
 }}}
 
-
+ == 修改 ==
+
+此程式碼用hadoop 0.20的api 將 deprecated 修正，然而卻出現以下錯誤
+
+{{{
+#!text
+
+ Exception in thread "main" java.lang.NullPointerException
+at WordCountV020.run(WordCountV020.java:127)
+at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
+at WordCountV020.main(WordCountV020.java:147)
+
+}}}
+
+=== 修改後原始碼 ===
+
+{{{
+#!java
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+import java.util.StringTokenizer;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.conf.Configured;
+import org.apache.hadoop.filecache.DistributedCache;
+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.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;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.util.Tool;
+import org.apache.hadoop.util.ToolRunner;
+
+public class WordCountV020 extends Configured implements Tool {
+
+        static boolean caseSensitive = true;
+        static Set<String> patternsToSkip = new HashSet<String>();
+
+        static void parseSkipFile(Path patternsFile) {
+                try {
+                        BufferedReader fis = new BufferedReader(new FileReader(patternsFile
+                                        .toString()));
+                        String pattern = null;
+                        while ((pattern = fis.readLine()) != null) {
+                                patternsToSkip.add(pattern);
+                        }
+                } catch (IOException ioe) {
+                        System.err
+                                        .println("Caught exception while parsing the cached file '"
+                                                        + patternsFile + "' : "
+                                                        + StringUtils.stringifyException(ioe));
+                }
+        }
+
+        public static class Map extends
+                        Mapper<LongWritable, Text, Text, IntWritable> {
+
+                static enum Counters {
+                        INPUT_WORDS
+                }
+
+                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 = (caseSensitive) ? value.toString() : value.toString()
+                                        .toLowerCase();
+
+                        for (String pattern : patternsToSkip) {
+                                line = line.replaceAll(pattern, "");
+                        }
+
+                        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, Iterator<IntWritable> values, Context context)
+                                throws IOException, InterruptedException {
+                        int sum = 0;
+                        while (values.hasNext()) {
+                                sum += values.next().get();
+                        }
+                        context.write(key, new IntWritable(sum));
+                }
+        }
+
+        public int run(String[] args) throws Exception {
+
+                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);
+
+                job.setOutputKeyClass(Text.class);
+                job.setOutputValueClass(IntWritable.class);
+
+                job.setMapperClass(Map.class);
+                job.setCombinerClass(Reduce.class);
+                job.setReducerClass(Reduce.class);
+
+                List<String> other_args = new ArrayList<String>();
+                for (int i = 0; i < args.length; ++i) {
+                        if ("-skip".equals(args[i])) {
+                                DistributedCache
+                                                .addCacheFile(new Path(args[++i]).toUri(), conf);
+                                conf.setBoolean("wordcount.skip.patterns", true);
+                        } else {
+                                other_args.add(args[i]);
+                        }
+                }
+
+                caseSensitive = conf.getBoolean("wordcount.case.sensitive", true);
+
+                if (conf.getBoolean("wordcount.skip.patterns", false)) {
+                        Path[] patternsFiles = new Path[0];
+                        try {
+                                patternsFiles = DistributedCache.getLocalCacheFiles(conf);
+                                
+                        } catch (IOException ioe) {
+                                System.err
+                                                .println("Caught exception while getting cached files: "
+                                                                + StringUtils.stringifyException(ioe));
+                        }
+                        for (Path patternsFile : patternsFiles) {
+                                parseSkipFile(patternsFile);
+                        }
+                }
+
+                FileInputFormat.setInputPaths(job, new Path(other_args.get(0)));
+                // 設定輸出路徑
+                FileOutputFormat.setOutputPath(job, new Path(other_args.get(1)));
+
+                CheckAndDelete.checkAndDelete(other_args.get(1), conf);
+                job.waitForCompletion(true);
+                return 0;
+        }
+
+        public static void main(String[] args) throws Exception {
+                String[] argv = { "-Dwordcount.case.sensitive=false",
+                                "/user/waue/input", "/user/waue/output-v020", "-skip",
+                                "/user/waue/patterns/patterns.txt" };
+                args = argv;
+                int res = ToolRunner
+                                .run(new Configuration(), new WordCountV020(), args);
+                System.exit(res);
+        }
+}
+}}}