Spark从HDFS上读取JSON数据

代码如下：

import org.apache.spark.sql.Row;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.VoidFunction;
import org.apache.spark.sql.DataFrame;
import org.apache.spark.sql.SQLContext;public class QueryHDFSData {static SparkConf sparkConf = new SparkConf().setAppName("HDFSQuery").setMaster("local[2]");static JavaSparkContext sc = new JavaSparkContext(sparkConf);static SQLContext sqlContext = new SQLContext(sc);public static void main(String[] args){
//        JavaRDD<String> poi = sc.textFile("hdfs://node2:9000/user/flume/events/2015-11-27-21/events-.1448629506841");DataFrame df = sqlContext.read().json("hdfs://node2:9000/user/flume/events/2015-11-26-21/events-.1448543965316");// 打印模式
        df.printSchema();// 将数据框架注册成一个表df.registerTempTable("poi");// 使用sql语句从表中读取数据DataFrame poi = sqlContext.sql("SELECT * FROM poi WHERE cid=57425749418");JavaRDD<Row> row = poi.javaRDD();row.foreach(new VoidFunction<Row>(){@Overridepublic void call(Row r) throws Exception {System.out.println(r.mkString());        }});}
}