java - 即使已实现，也会收到工具界面警告

Question

我有一个非常简单的“Hello world”风格的 map/reduce 作业。

public class Tester extends Configured implements Tool {

    @Override
    public int run(String[] args) throws Exception {
        if (args.length != 2) {
            System.err.printf("Usage: %s [generic options] <input> <output>\n",
                getClass().getSimpleName());
            ToolRunner.printGenericCommandUsage(System.err);
            return -1;
        }

        Job job = Job.getInstance(new Configuration());
        job.setJarByClass(getClass());


        getConf().set("mapreduce.job.queuename", "adhoc");

        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(NullWritable.class);
        job.setMapperClass(TesterMapper.class);
        job.setNumReduceTasks(0);

        return job.waitForCompletion(true) ? 0 : 1;
    }

    public static void main(String[] args) throws Exception {
        int exitCode = ToolRunner.run(new Tester(), args);
        System.exit(exitCode);
    }

它实现了 ToolRunner，但运行时不解析参数。

$hadoop jar target/manifold-mapreduce-0.1.0.jar ga.manifold.mapreduce.Tester -conf conf.xml etl/manifold/pipeline/ABV1T/ingest/input etl/manifold/pipeline/ABV1T/ingest/output
15/02/04 16:35:24 INFO client.RMProxy: Connecting to ResourceManager at lxjh116-pvt.phibred.com/10.56.100.23:8050
15/02/04 16:35:25 WARN mapreduce.JobSubmitter: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.

我可以验证没有添加配置。

有人知道为什么 Hadoop 认为 ToolRunner 没有实现吗？

$hadoop 版本 Hadoop 2.4.0.2.1.2.0-402

霍顿工厂

谢谢， 克里斯

Answer 1

由于您的问题在 Google 搜索此警告的顶部的速度非常快，因此我将在此处给出正确的答案:

正如 user1797538 你 所说:(对此感到抱歉)

user1797538: "The problem was the call to get a Job instance"

必须使用父类(super class) Configured。顾名思义，它已经配置好了，所以Tester类必须使用现有的Configuration，不能设置一个新的空Configuration。

如果我们在方法中提取作业创建:

private Job createJob() throws IOException {

    // On this line use getConf() instead of new Configuration()
    Job job = Job.getInstance(getConf(), Tester.class.getCanonicalName());

    // Other job setter call here, for example
    job.setJarByClass(Tester.class);
    job.setMapperClass(TesterMapper.class);
    job.setCombinerClass(TesterReducer.class);
    job.setReducerClass(TesterReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    // adapt this to your needs of course.

    return job;
}

javadoc 中的另一个示例:org.apache.hadoop.util.Tool

还有 Javadoc:Configured.getConf()