使用随机数以及扩容表进行join代码

        /**
         * 使用随机数和扩容表进行join
         */
        
        JavaPairRDD<String, Row> expandedRDD = userid2InfoRDD.flatMapToPair(
                
                new PairFlatMapFunction<Tuple2<Long,Row>, String, Row>() {

                    private static final long serialVersionUID = 1L;

                    @Override
                    public Iterable<Tuple2<String, Row>> call(Tuple2<Long, Row> tuple)
                            throws Exception {
                        List<Tuple2<String, Row>> list = new ArrayList<Tuple2<String, Row>>();
                        
                        for(int i = 0; i < 10; i++) {
                            list.add(new Tuple2<String, Row>(0 + "_" + tuple._1, tuple._2));
                        }
                        
                        return list;
                    }
                    
                });
        
        JavaPairRDD<String, String> mappedRDD = userid2PartAggrInfoRDD.mapToPair(
                
                new PairFunction<Tuple2<Long,String>, String, String>() {

                    private static final long serialVersionUID = 1L;

                    @Override
                    public Tuple2<String, String> call(Tuple2<Long, String> tuple)
                            throws Exception {
                        Random random = new Random();
                        int prefix = random.nextInt(10);
                        return new Tuple2<String, String>(prefix + "_" + tuple._1, tuple._2);  
                    }
                    
                });
        
        JavaPairRDD<String, Tuple2<String, Row>> joinedRDD = mappedRDD.join(expandedRDD);
        
        JavaPairRDD<String, String> finalRDD = joinedRDD.mapToPair(
                
                new PairFunction<Tuple2<String,Tuple2<String,Row>>, String, String>() {

                    private static final long serialVersionUID = 1L;

                    @Override
                    public Tuple2<String, String> call(
                            Tuple2<String, Tuple2<String, Row>> tuple)
                            throws Exception {
                        String partAggrInfo = tuple._2._1;
                        Row userInfoRow = tuple._2._2;
                        
                        String sessionid = StringUtils.getFieldFromConcatString(
                                partAggrInfo, "\|", Constants.FIELD_SESSION_ID);
                        
                        int age = userInfoRow.getInt(3);
                        String professional = userInfoRow.getString(4);
                        String city = userInfoRow.getString(5);
                        String sex = userInfoRow.getString(6);
                        
                        String fullAggrInfo = partAggrInfo + "|"
                                + Constants.FIELD_AGE + "=" + age + "|"
                                + Constants.FIELD_PROFESSIONAL + "=" + professional + "|"
                                + Constants.FIELD_CITY + "=" + city + "|"
                                + Constants.FIELD_SEX + "=" + sex;
                        
                        return new Tuple2<String, String>(sessionid, fullAggrInfo);
                    }
                    
                });