dataframe 을 만 드 는 몇 가지 방법 - json 형식의 파일 을 읽 습 니 다.

SparkConf conf = new SparkConf();
conf.setMaster("local").setAppName("jsonfile");
SparkContext sc = new SparkContext(conf);
		
//  sqlContext
SQLContext sqlContext = new SQLContext(sc);
		
/**
 * DataFrame         RDD  RDD    Row  。
 *            json     
 */
 DataFrame df = sqlContext.read().format("json").load("sparksql/json");
// DataFrame df2 = sqlContext.read().json("sparksql/json.txt");
// df2.show();
 /**
  * DataFrame   RDD
  */
 RDD rdd = df.rdd();
/**
 *    DataFrame    ，     20 。            show(  )
 *   ：      ，            ascii     。
 */
// df.show();
/**
 *        schema  
 */
 df.printSchema();
		
 /**
  * dataFram   API   DataFrame
  */
  //select name from table
 // df.select("name").show();
 //select name age+10 as addage from table
	 df.select(df.col("name"),df.col("age").plus(10).alias("addage")).show();
 //select name ,age from table where age>19
	 df.select(df.col("name"),df.col("age")).where(df.col("age").gt(19)).show();
 //select count(*) from table group by age
 df.groupBy(df.col("age")).count().show();
		
 /**
   *  DataFrame         ，           ，      ，       
  */
 df.registerTempTable("jtable");
		
 DataFrame sql = sqlContext.sql("select age,count(1) from jtable group by age");
 DataFrame sql2 = sqlContext.sql("select * from jtable");
		
 sc.stop();

DataFrame df = sqlContext.read().format("json").load("sparksql/json");
// DataFrame df2 = sqlContext.read().json("sparksql/json.txt");

val conf = new SparkConf()
conf.setMaster("local").setAppName("jsonfile")

val sc = new SparkContext(conf)
val sqlContext = new SQLContext(sc)
val df = sqlContext.read.json("sparksql/json")  
//val df1 = sqlContext.read.format("json").load("sparksql/json")

df.show()
df.printSchema()
//select * from table
df.select(df.col("name")).show()
//select name from table where age>19
df.select(df.col("name"),df.col("age")).where(df.col("age").gt(19)).show()
//select count(*) from table group by age
df.groupBy(df.col("age")).count().show();
 
/**
 *      
 */
df.registerTempTable("jtable")
val result  = sqlContext.sql("select  * from jtable")
result.show()
sc.stop()