No new data sinks have been defined since the last execution

报错：

Exception in thread "main" java.lang.RuntimeException: No new data sinks have been defined since the last execution. The last execution refers to the latest call to 'execute()', 'count()', 'collect()', or 'print()'.
    at org.apache.flink.api.java.ExecutionEnvironment.createProgramPlan(ExecutionEnvironment.java:944)
    at org.apache.flink.api.java.ExecutionEnvironment.createProgramPlan(ExecutionEnvironment.java:926)
    at org.apache.flink.api.java.LocalEnvironment.execute(LocalEnvironment.java:85)
    at org.apache.flink.api.java.ExecutionEnvironment.execute(ExecutionEnvironment.java:820)
    at org.apache.flink.api.scala.ExecutionEnvironment.execute(ExecutionEnvironment.scala:525)
    at com.yxf.wordcount.BatchWordCount$.main(BatchWordCount.scala:15)
    at com.yxf.wordcount.BatchWordCount.main(BatchWordCount.scala)

代码：

object BatchWordCount {
    
    
 
    def main(args: Array[String]): Unit = {
    
    
        val env: ExecutionEnvironment = ExecutionEnvironment.getExecutionEnvironment
        val line: DataSet[String] = env.readTextFile("input")
        val result: AggregateDataSet[(String, Int)] = line.flatMap(_.split(" ")).map((_, 1)).groupBy(0).sum(1)
        result.print()
        env.execute()
    }
}

问题解决：
异常的原因就是说，自上次执行以来，没有定义新的数据接收器。对于离线批处理的算子，如：“count()”、“collect()”或“print()”等既有sink功能，还有触发的功能。我们上面调用了print()方法，会自动触发execute，所以最后面的一行执行器没有数据可以执行。
对于学过sparkstreaming后初学flink的小伙伴来说，这里要注意一下，有点小区别。