创建dataframe的几种方式——读取json格式的RDD

一、Java代码

SparkConf conf = new SparkConf();
conf.setMaster("local").setAppName("jsonRDD");
JavaSparkContext sc = new JavaSparkContext(conf);
SQLContext sqlContext = new SQLContext(sc);
JavaRDD<String> nameRDD = sc.parallelize(Arrays.asList(
	"{"name":"zhangsan","age":"18"}",
	"{"name":"lisi","age":"19"}",
	"{"name":"wangwu","age":"20"}"
));
JavaRDD<String> scoreRDD = sc.parallelize(Arrays.asList(
"{"name":"zhangsan","score":"100"}",
"{"name":"lisi","score":"200"}",
"{"name":"wangwu","score":"300"}"
));

DataFrame namedf = sqlContext.read().json(nameRDD);
DataFrame scoredf = sqlContext.read().json(scoreRDD);
namedf.registerTempTable("name");
scoredf.registerTempTable("score");

DataFrame result = sqlContext.sql("select name.name,name.age,score.score from name,score where name.name = score.name");
result.show();

sc.stop();

二、Scala代码

val conf = new SparkConf()
conf.setMaster("local").setAppName("jsonrdd")
val sc = new SparkContext(conf)
val sqlContext = new SQLContext(sc)

val nameRDD = sc.makeRDD(Array(
  "{"name":"zhangsan","age":18}",
  "{"name":"lisi","age":19}",
  "{"name":"wangwu","age":20}"
))
val scoreRDD = sc.makeRDD(Array(
		"{"name":"zhangsan","score":100}",
		"{"name":"lisi","score":200}",
		"{"name":"wangwu","score":300}"
		))
val nameDF = sqlContext.read.json(nameRDD)
val scoreDF = sqlContext.read.json(scoreRDD)
nameDF.registerTempTable("name") 		
scoreDF.registerTempTable("score") 		
val result = sqlContext.sql("select name.name,name.age,score.score from name,score where name.name = score.name")
result.show()
sc.stop()

最后

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