MapReduceBase 和 Mapper 已弃用 [英] MapReduceBase and Mapper deprecated

问题描述

public static class Map extends MapReduceBase implements Mapper

MapReduceBase、Mapper 和 JobConf 在 Hadoop 0.20.203 中已弃用.

MapReduceBase, Mapper and JobConf are deprecated in Hadoop 0.20.203.

我们现在应该使用什么?

What should we use now?

Edit 1 - 对于 Mapper 和 MapReduceBase，我发现我们只需要扩展 Mapper

Edit 1 - for the Mapper and the MapReduceBase, I found that we just need to extends the Mapper

public static class Map 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);
    }
  }
}

Edit 2 - 对于 JobConf 我们应该使用这样的配置:

Edit 2 - For JobConf we should use configuration like this:

public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        Job job = new Job(conf);
        job.setMapperClass(WordCount.Map.class);
    }

编辑 3 - 我根据新 API 找到了一个很好的教程:http://sonerbalkir.blogspot.com/2010/01/new-hadoop-api-020x.html

Edit 3 - I found a good tutorial according to the new API : http://sonerbalkir.blogspot.com/2010/01/new-hadoop-api-020x.html

推荐答案

Javadoc 包含关于这个废弃类的使用信息:

Javadoc contains info what to use instaed of this depraceated classes:

例如http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/mapred/JobConf.html

 Deprecated. Use Configuration instead

当你使用maven并打开类声明(F3)maven可以自动下载源代码，你会看到javadoc注释的内容和解释.

When you use maven and open class declaration (F3) maven can automatically download source code and you'll see content of javadoc comments with explanations.

这篇关于MapReduceBase 和 Mapper 已弃用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！