Question

我编写了简单的示例来接收表，但是即使在实现了AppendTableSink接口之后也在Apache Flink中获得了这个异常。

    package com.cc.flink.functionUtils;

    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.Collection;
    import java.util.Iterator;

    import org.apache.flink.api.common.functions.IterationRuntimeContext;
    import org.apache.flink.api.common.functions.MapFunction;
    import org.apache.flink.api.common.functions.RichFunction;
    import org.apache.flink.api.common.io.OutputFormat;
    import org.apache.flink.api.common.typeinfo.TypeInformation;
    import org.apache.flink.api.java.io.LocalCollectionOutputFormat;
    import org.apache.flink.api.java.tuple.Tuple2;
    import org.apache.flink.api.java.typeutils.TupleTypeInfo;
    import org.apache.flink.configuration.Configuration;
    import org.apache.flink.contrib.streaming.DataStreamUtils;
    import org.apache.flink.streaming.api.datastream.DataStream;
    import org.apache.flink.streaming.api.datastream.DataStreamSink;
    import org.apache.flink.streaming.api.datastream.DataStreamSource;
    import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
    import org.apache.flink.streaming.api.functions.sink.SinkFunction;
    import org.apache.flink.streaming.connectors.rabbitmq.RMQSource;
    import org.apache.flink.streaming.connectors.rabbitmq.common.RMQConnectionConfig;
    import org.apache.flink.streaming.util.serialization.SimpleStringSchema;
    import org.apache.flink.table.api.Table;
    import org.apache.flink.table.api.TableEnvironment;
    import org.apache.flink.table.api.java.StreamTableEnvironment;
    import org.apache.flink.table.sinks.AppendStreamTableSink;
    import org.apache.flink.table.sinks.RetractStreamTableSink;
    import org.apache.flink.table.sinks.TableSink;
    import org.apache.flink.types.Row;




    public class MyTable implements AppendStreamTableSink<Row>{



        @Override
        public TableSink<Row> configure(String[] arg0, TypeInformation<?>[] arg1) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public String[] getFieldNames() {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public TypeInformation<?>[] getFieldTypes() {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public TypeInformation<Row> getOutputType() {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public void emitDataStream(DataStream<Row> arg0) {
            // TODO Auto-generated method stub
            arg0.print();

        }




        public static void main(String[] args) throws Exception {

            final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
            final RMQConnectionConfig connectionConfig = new RMQConnectionConfig.Builder()
                    .setHost("localhost")
                    .setVirtualHost("/")
                    .setUserName("guest")
                    .setPassword("guest")
                    .setPort(5672)
                    .build();


            final DataStream<String> stream = env
                    .addSource(new RMQSource<String>(
                            connectionConfig,            // config for the RabbitMQ connection
                            "test",                 // name of the RabbitMQ queue to consume
                            true,                        // use correlation ids; can be false if only at-least-once is required
                            new SimpleStringSchema()))   // deserialization schema to turn messages into Java objects
                    .setParallelism(1);   



            final ArrayList<String> values = new ArrayList<>();
            StreamTableEnvironment StreamTableEnv = TableEnvironment.getTableEnvironment(env);
            Table fromDataStream = StreamTableEnv.fromDataStream(stream,
                    "member_id");
            StreamTableEnv.registerTable("emp1",fromDataStream);
            Table output =StreamTableEnv.sql("select count(*) from emp1 where member_id Like '%test%'");
            fromDataStream.writeToSink(new MyTable() );
            env.execute();

        }

    }

log4j：WARN找不到logger（org.apache.calcite.sql.parser）的appender。   log4j：WARN请正确初始化log4j系统。   log4j：WARN请参阅http://logging.apache.org/log4j/1.2/faq.html#noconfig了解更多信息

线程“main”中的异常org.apache.flink.table.api.TableException：流表只能由AppendStreamTableSink，RetractStreamTable
发出
at org.apache.flink.table.api.StreamTableenvironment.writeToSink（StreamTableenvironment.scala：219）

at org.apache.flink.table.api.Table.writeToSink（table.scala：800）

at org.apache.flink.table.api.Table.writeToSink（table.scala：773）

at com.cc.flink.functionutils.MyTable.main（MyTable.java:103）

Answer 1

您的示例中的问题是您尝试使用AppendTableSink，但您的查询会产生撤消。这是由于您的陈述中的COUNT(*)。每当新行到达时，旧的发射计数不再有效，需要撤回。

如果它只是SELECT *，那么每个传入的行都会产生一个不影响前一行的输出行。

即使在apache flink中实现AppendTableStream接口后也会出现以下错误

1 个答案: