Flink--Transform(简单转换算子)

Flink中的简单转换算子 包含 map flatmap fiter
他们有一个共同的特点就是 1 to 1 类似于spark窄依赖

输入一个 按照转换规则 输出一个

	 //创建执行环境
    val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment

    //读取一个list并转换为datastream
    val intList = List(1,2,3,4,5,6,7,8,9,10)
    val intDataStream: DataStream[Int] = env.fromCollection(intList)

    //进行map操作
    val mapedDataStream: DataStream[Int] = intDataStream.map(x => x * 2)

    //打印
    mapedDataStream.print()

    //执行
    env.execute("apitest")

map 之后做了一个flat扁平化

//创建执行环境
val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment
    
val flatmapData: DataStream[String] = env.fromCollection(List("a b","c d"))
val flatmapedData: DataStream[String] = flatmapData.flatMap(x => x.split(" "))
flatmapedData.print()

//执行
env.execute("apitest")

由
List(“a b”,“c d”)
变为
a b c d

给一个表达式 返回布尔类型结果
判断是否为true来判断是否保留。

//创建执行环境
val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment

val filterData: DataStream[Int] = env.fromCollection(List(1,2,3))
val fiteredData: DataStream[Int] = filterData.filter(x => x == 1)
fiteredData.print()
    
//执行
env.execute("apitest")

由
List(1,2,3)
变为
1