Java样例代码
功能简介
统计日志文件中本周末网购停留总时间超过2个小时的女性网民信息。
代码样例
下面代码片段仅为演示,具体代码参见com.huawei.bigdata.spark.examples.FemaleInfoCollection:
SparkConf conf = new SparkConf().setAppName("CollectFemaleInfo");
JavaSparkContext jsc = new JavaSparkContext(conf);
SQLContext sqlContext = new org.apache.spark.sql.SQLContext(jsc);
// 通过隐式转换,将RDD转换成DataFrame
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;
}
});
// 注册表。
DataFrame schemaFemaleInfo = sqlContext.createDataFrame(femaleInfoJavaRDD,FemaleInfo.class);
schemaFemaleInfo.registerTempTable("FemaleInfoTable");
// 执行SQL查询
DataFrame femaleTimeInfo = sqlContext.sql("select * from " +
"(select name,sum(stayTime) as totalStayTime from FemaleInfoTable " +
"where gender = 'female' group by name )" +
" tmp where totalStayTime >120");
// 显示结果。
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();
上面是简单示例,其它sparkSQL特性请参见如下链接:http://spark.apache.org/docs/latest/sql-programming-guide.html#running-sql-queries-programmatically。