hadoop reduce 的问题,大神帮帮忙吧
我的reduce为什么执行了两次啊?代码如下:
public static class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable>{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
String str = itr.nextToken() ;
word.set(str);
System.out.println(str);
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text,IntWritable,Text,IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
System.out.println(key.toString()+"------>"+val) ;
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
if (otherArgs.length != 2) {
System.err.println("Usage: wordcount <in> <out>");
System.exit(2);
}
Job job = new Job(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
// job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setInputFormatClass(TextInputFormat.class) ;
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
但是控制台输出却是这样:
gao------>1
gao------>1
hello------>1
hello------>1
hello------>1
hello------>1
li------>1
li------>1
按我的理解应该是这样的啊:
gao------>1
hello------>1
hello------>1
li------>1
大神给帮帮忙!! --------------------编程问答-------------------- 你的输入文件内容是什么样子的? --------------------编程问答-------------------- 别急,你自己仔细看下你的源程序,你的map函数和reduce函数都有输出。
补充:云计算 , OpenAPI