【云星数据---Apache Flink实战系列(精品版)】：Apache Flink批处理API详解与编程实战015--DateSet实用API详解015

DateSet的API详解十五

getParallelism

def getParallelism: IntReturns the parallelism of this operation.获取DataSet的并行度。

执行程序：

//1.创建一个 DataSet其元素为String类型val input0: DataSet[String] = benv.fromElements("A", "B", "C")//2.获取DataSet的并行度。input0.getParallelism

执行结果：

res98: Int = 1

setParallelism

def setParallelism(parallelism: Int): DataSet[T]Sets the parallelism of this operation. This must be greater than 1.设置DataSet的并行度，设置的并行度必须大于1

执行程序：

//1.创建一个 DataSet其元素为String类型val input0: DataSet[String] = benv.fromElements("A", "B", "C")//2.设置DataSet的并行度。input0.setParallelism(2)//3.获取DataSet的并行度。input0.getParallelism

执行结果：

res102: Int = 2

writeAsText

def writeAsText(filePath: String, writeMode: WriteMode = null): DataSink[T]Writes this DataSet to the specified location.将DataSet写出到存储系统。不同的存储系统写法不一样。hdfs文件路径：    hdfs:///path/to/data本地文件路径：    file:///path/to/data

执行程序：

//1.创建 DataSet[Student]case class Student(age: Int, name: String,height:Double)val input: DataSet[Student] = benv.fromElements(Student(16,"zhangasn",194.5),Student(17,"zhangasn",184.5),Student(18,"zhangasn",174.5),Student(16,"lisi",194.5),Student(17,"lisi",184.5),Student(18,"lisi",174.5))//2.将DataSet写出到存储系统input.writeAsText("hdfs:///output/flink/dataset/testdata/students.txt")//3.执行程序benv.execute()

hadoop web ui中的执行效果：

terminal中查看文件效果：