我试图在本地模式下在Apache Flink中执行示例程序.
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;
public class WordCountExample {
public static void main(String[] args) throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
DataSet<String> text = env.fromElements(
"Who's there?","I think I hear them. Stand,ho! Who's there?");
//DataSet<String> text1 = env.readTextFile(args[0]);
DataSet<Tuple2<String,Integer>> wordCounts = text
.flatMap(new LineSplitter())
.groupBy(0)
.sum(1);
wordCounts.print();
env.execute();
env.execute("Word Count Example");
}
public static class LineSplitter implements FlatMapFunction<String,Tuple2<String,Integer>> {
@Override
public void flatMap(String line,Collector<Tuple2<String,Integer>> out) {
for (String word : line.split(" ")) {
out.collect(new Tuple2<String,Integer>(word,1));
}
}
}
}
它给了我例外：
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/mapreduce/InputFormat
at WordCountExample.main(WordCountExample.java:10)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.mapreduce.InputFormat
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 1 more
我究竟做错了什么？
我也使用过正确的罐子.
弗林克的Java-0.9.0-里程碑,1.jar
弗林克的客户端-0.9.0-里程碑,1.jar
弗林克核-0.9.0-里程碑,1.jar
解决方法
在项目中添加三个Flink Jar文件作为依赖项是不够的,因为它们具有其他传递依赖性,例如在Hadoop上.
获得开发(和本地执行)Flink程序的工作设置的最简单方法是遵循使用Maven原型配置Maven项目的quickstart guide.可以将此Maven项目导入IDE.
