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我在Apache Flink 1.3.2中嘗試了幾個flink translate（）函數：一個來自BatchTableEnvironment，另一個來自StreamTableEnvironment。該方案給了我錯誤，我迷路了。下面的程序在運行時拋出異常（不知道它需要什麼TypeInformation）。它只是使用應該與結果所需相匹配的類型信息。但它不起作用，有幫助嗎？我想我提供所有的細節......在Apache Flink的TypeInformation 1.3.2 BatchTableEnvironment的翻譯方法
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.table.api.BatchTableEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.TableEnvironment;
/**
*
* @author Paul Z. Wu Oct 28, 2017
*/
public class TableEnv {
public static void main(String s[]) throws Exception {
ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
BatchTableEnvironment tEnv = TableEnvironment.getTableEnvironment(env);
DataSet<WC> input = env.fromElements(
new WC("Hello", 1),
new WC("Ciao", 1),
new WC("Hello", 1));
tEnv.registerDataSetInternal("abc", input);
Table table = tEnv.scan("abc");
Table wordCounts = table
.groupBy("word")
.select("word, count.sum as count");
System.out.println(wordCounts.getSchema());
DataSet<WC> a = tEnv.translate(wordCounts, TypeInformation.of(WC.class));
a.print();
}
public static class WC {
public WC(String word, int count) {
this.word = word;
this.count = count;
}
public WC() {
} // empty constructor to satisfy POJO requirements
public String word;
public int count;
}
}
唯一的例外是：
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/api/scala/typeutils/CaseClassTypeInfo
at org.apache.flink.table.codegen.CodeGenUtils$.fieldAccessorFor(CodeGenUtils.scala:236)
at org.apache.flink.table.codegen.CodeGenerator.org$apache$flink$table$codegen$CodeGenerator$$generateFieldAccess(CodeGenerator.scala:1654)
at org.apache.flink.table.codegen.CodeGenerator.org$apache$flink$table$codegen$CodeGenerator$$generateInputAccess(CodeGenerator.scala:1602)
at org.apache.flink.table.codegen.CodeGenerator$$anonfun$23.apply(CodeGenerator.scala:875)
at org.apache.flink.table.codegen.CodeGenerator$$anonfun$23.apply(CodeGenerator.scala:874)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.ArrayOps$ofInt.foreach(ArrayOps.scala:234)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
at scala.collection.mutable.ArrayOps$ofInt.map(ArrayOps.scala:234)
at org.apache.flink.table.codegen.CodeGenerator.generateConverterResultExpression(CodeGenerator.scala:874)
at org.apache.flink.table.plan.nodes.CommonScan$class.generatedConversionFunction(CommonScan.scala:57)
at org.apache.flink.table.plan.nodes.dataset.DataSetScan.generatedConversionFunction(DataSetScan.scala:36)
at org.apache.flink.table.plan.nodes.dataset.BatchScan$class.convertToInternalRow(BatchScan.scala:48)
at org.apache.flink.table.plan.nodes.dataset.DataSetScan.convertToInternalRow(DataSetScan.scala:36)
at org.apache.flink.table.plan.nodes.dataset.DataSetScan.translateToPlan(DataSetScan.scala:65)
at org.apache.flink.table.api.BatchTableEnvironment.translate(BatchTableEnvironment.scala:350)
at org.apache.flink.table.api.BatchTableEnvironment.translate(BatchTableEnvironment.scala:329)
at com.att.ariso.TableEnv.main(TableEnv.java:39)
Caused by: java.lang.ClassNotFoundException: org.apache.flink.api.scala.typeutils.CaseClassTypeInfo
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 20 more
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