Java Sample Code

Updated on 2022-09-14 GMT+08:00

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Function Description

Collect statistics on female netizens who dwell on online shopping for more than 2 hours on the weekend.

Sample Code

The following code snippets are used as an example. For complete codes, see the com.huawei.bigdata.spark.examples.FemaleInfoCollection class.

    // Create a configuration class SparkConf, and then create a SparkContext.
    SparkConf conf = new SparkConf().setAppName("CollectFemaleInfo");
    JavaSparkContext jsc = new JavaSparkContext(conf);

    // Read the original file data, and transfer each row of records to an element of the RDD.
    JavaRDD<String> data = jsc.textFile(args[0]);

    // Split each column of each record to generate a Tuple.
    JavaRDD<Tuple3<String,String,Integer>> person = data.map(new Function<String,Tuple3<String,String,Integer>>()
    {
        private static final long serialVersionUID = -2381522520231963249L;

        @Override
        public Tuple3<String, String, Integer> call(String s) throws Exception
        {
            // Split a row of data by commas (,).
            String[] tokens = s.split(",");

            // Integrate the three split elements to a ternary Tuple.
            Tuple3<String, String, Integer> person = new Tuple3<String, String, Integer>(tokens[0], tokens[1], Integer.parseInt(tokens[2]));
            return person;
        }
    });

    // Use the filter function to filter the data information about the time that female netizens spend online.
    JavaRDD<Tuple3<String,String,Integer>> female = person.filter(new Function<Tuple3<String,String,Integer>, Boolean>()
    {
        private static final long serialVersionUID = -4210609503909770492L;

        @Override
        public Boolean call(Tuple3<String, String, Integer> person) throws Exception
        {
            // Filter the records of which the gender in the second column is female.
            Boolean isFemale = person._2().equals("female");
            return isFemale;
        }
    });

    // Summarize the total time that each female netizen spends online. 
    JavaPairRDD<String, Integer> females = female.mapToPair(new PairFunction<Tuple3<String, String, Integer>, String, Integer>()
    {
        private static final long serialVersionUID = 8313245377656164868L;

        @Override
        public Tuple2<String, Integer> call(Tuple3<String, String, Integer> female) throws Exception
        {
            // Extract the two columns representing the name and dwell duration for the sum of dwell duration by name during further operations. 
            Tuple2<String, Integer> femaleAndTime = new  Tuple2<String, Integer>(female._1(), female._3());
            return femaleAndTime;
        }
    });
      JavaPairRDD<String, Integer> femaleTime = females.reduceByKey(new Function2<Integer, Integer, Integer>()
    {
        private static final long serialVersionUID = -3271456048413349559L;

        @Override
        public Integer call(Integer integer, Integer integer2) throws Exception
        {
            // Sum the two dwell durations of the same female netizen.
            return (integer + integer2);
        }
    });

    // Filter the information of female netizens who spend more than 2 hours online.
    JavaPairRDD<String, Integer> rightFemales = females.filter(new Function<Tuple2<String, Integer>, Boolean>()
    {
        private static final long serialVersionUID = -3178168214712105171L;

        @Override
        public Boolean call(Tuple2<String, Integer> s) throws Exception
        {
            // Extract the total time that female netizens spend online, and determine whether the time is more than 2 hours.
            if(s._2() > (2 * 60))
            {
                return true;
            }
            return false;
        }
    });

    // Print the information about female netizens who meet the requirements.
    for(Tuple2<String, Integer> d: rightFemales.collect())
    {
        System.out.println(d._1() + "," + d._2());
    }

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