NoClassDefFoundError: org/apache/flink/metrics/MetricGroup

碰到这么个问题:

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/metrics/MetricGroup
    at org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1614)
    at org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.fromCollection(StreamExecutionEnvironment.java:975)
    at org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.fromCollection(StreamExecutionEnvironment.java:945)
    at Map.main(Map.java:22)
Caused by: java.lang.ClassNotFoundException: org.apache.flink.metrics.MetricGroup
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 4 more

显然首先去$FLINK_HOME下面输入

grep -r MetricGroup

返回结果是:

flink-dist_2.11-1.12-SNAPSHOT.jar

在mvnrepository.com中搜不到flink-dist

实在没办法了,卡了老久,最后一个办法如下 :

直接在Project Structure中导入$FLINK_HOME/lib下面的flink-dist-***.jar

然后再次运行代码,问题解决.