public static class TokenizerMapper extends Mapper<Object, Text, Text, Text> {
public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString(), " *$&#/\t\n\f\"'\\,.:;?![](){}<>~-_");
while (itr.hasMoreTokens()) {
String term = itr.nextToken().toLowerCase();
List<Pair<String, Pair<Integer, Integer>>> map = new ArrayList<Pair<String, Pair<Integer, Integer>>>();
/*here i am performing some operations*/
for (Pair<String, Pair<Integer, Integer>> i : map){
String w1 = i.getKey();
Text word = new Text(w1);
Pair<Integer, Integer> newValue = i.getValue();
String merge = String.valueOf(newValue.getKey()) + " " + String.valueOf(newValue.getValue());
Text val = new Text(merge);
/*sending both the arguments as text into my context.*/
context.write(word, val);
}
}
}
}
public static class Reducer1 extends Reducer<Text, Text, Text, Text> {
public void reduce(Text key, Text values, Context context) throws IOException, InterruptedException {
/* here i want to extract the values, i tried using for loop but its saying cannot iterate, its expecting something iterable.*/
for (Text t : values)
{
/*this is not working. I know we can use Iterable<IntWritable> for integers but in my case it is text.
}
//context.write(key, values);
}
}
请查看注释行以更好地了解我的问题。
有什么方法可以提取化简器中的Text值。
For
循环需要iterable
。
最佳答案
在化简器中,您将得到一个Iterable<Text>
,您必须在其上循环并在一个空格上分割以为映射器编写的每个merge
字符串重新创建String值。
注意:如果 map 中的newValue.getKey()
包含字符串本身,则在空格上分割将不是很可靠
关于java - Hadoop Map减少Java,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52159056/