Demo1

Posted 2020-11-19 huiandong

package com.bjsxt.spark.others;

import java.util.Arrays;
import java.util.List;

import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.Function;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFunction;
import org.apache.spark.api.java.function.VoidFunction;

import scala.Tuple2;
/**
* 动态统计出现次数最多的单词个数，过滤掉。
* @author root
*
*/
public class Demo1 {
public static void main(String[] args) {
SparkConf conf = new SparkConf();
conf.setMaster("local").setAppName("demo1");
JavaSparkContext jsc = new JavaSparkContext(conf);
JavaRDD<String> lines = jsc.textFile("./records.txt");
JavaRDD<String> flatMap = lines.flatMap(new FlatMapFunction<String, String>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Iterable<String> call(String t) throws Exception {
return Arrays.asList(t.split(" "));
}
});
JavaPairRDD<String, Integer> mapToPair = flatMap.mapToPair(new PairFunction<String,String, Integer>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Tuple2<String, Integer> call(String t) throws Exception {
return new Tuple2<String, Integer>(t, 1);
}
});

JavaPairRDD<String, Integer> sample = mapToPair.sample(true, 0.5);

final List<Tuple2<String, Integer>> take = sample.reduceByKey(new Function2<Integer,Integer,Integer>(){

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Integer call(Integer v1, Integer v2) throws Exception {
return v1+v2;
}

}).mapToPair(new PairFunction<Tuple2<String,Integer>, Integer, String>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Tuple2<Integer, String> call(Tuple2<String, Integer> t)
throws Exception {
return new Tuple2<Integer, String>(t._2, t._1);
}
}).sortByKey(false).mapToPair(new PairFunction<Tuple2<Integer,String>, String, Integer>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Tuple2<String, Integer> call(Tuple2<Integer, String> t)
throws Exception {
return new Tuple2<String, Integer>(t._2, t._1);
}
}).take(1);

System.out.println("take--------"+take);

JavaPairRDD<String, Integer> result = mapToPair.filter(new Function<Tuple2<String,Integer>, Boolean>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Boolean call(Tuple2<String, Integer> v1) throws Exception {
return !v1._1.equals(take.get(0)._1);
}
}).reduceByKey(new Function2<Integer,Integer,Integer>(){

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Integer call(Integer v1, Integer v2) throws Exception {
return v1+v2;
}

}).mapToPair(new PairFunction<Tuple2<String,Integer>, Integer, String>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Tuple2<Integer, String> call(Tuple2<String, Integer> t)
throws Exception {
return new Tuple2<Integer, String>(t._2, t._1);
}
}).sortByKey(false).mapToPair(new PairFunction<Tuple2<Integer,String>, String, Integer>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public Tuple2<String, Integer> call(Tuple2<Integer, String> t)
throws Exception {
return new Tuple2<String, Integer>(t._2, t._1);
}
});

result.foreach(new VoidFunction<Tuple2<String,Integer>>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public void call(Tuple2<String, Integer> t) throws Exception {
System.out.println(t);
}
});

jsc.stop();

}
}