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Java Sample Code

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.

        SparkConf conf = new SparkConf().setAppName("CollectFemaleInfo");
        JavaSparkContext jsc = new JavaSparkContext(conf);
        SQLContext sqlContext = new org.apache.spark.sql.SQLContext(jsc);

        // Convert RDD to DataFrame through the implicit conversion.
        JavaRDD<FemaleInfo> femaleInfoJavaRDD = jsc.textFile(args[0]).map(
                new Function<String, FemaleInfo>() {
                    @Override
                    public FemaleInfo call(String line) throws Exception {
                        String[] parts = line.split(",");

                        FemaleInfo femaleInfo = new FemaleInfo();
                        femaleInfo.setName(parts[0]);
                        femaleInfo.setGender(parts[1]);
                        femaleInfo.setStayTime(Integer.parseInt(parts[2].trim()));
                        return femaleInfo;
                    }
                });

        // Register a table.
        DataFrame schemaFemaleInfo = sqlContext.createDataFrame(femaleInfoJavaRDD,FemaleInfo.class);
        schemaFemaleInfo.registerTempTable("FemaleInfoTable");

        // Execute an SQL query.
        DataFrame femaleTimeInfo = sqlContext.sql("select * from " +
                "(select name,sum(stayTime) as totalStayTime from FemaleInfoTable " +
                "where gender = 'female' group by name )" +
                " tmp where totalStayTime >120");

       // Display the result.
        List<String> result = femaleTimeInfo.javaRDD().map(new Function<Row, String>() {
            public String call(Row row) {
                return row.getString(0) + "," + row.getLong(1);
            }
        }).collect();
        System.out.println(result);
        jsc.stop();

For details about the code of other Spark SQL features, visit http://spark.apache.org/docs/latest/sql-programming-guide.html#running-sql-queries-programmatically.

Parent topic: Spark SQL Application