在Flink中,可以使用Flink的Table API或DataStream API来将int列聚合到array<int>。下面是两种方法的示例:
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.TableEnvironment;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.types.Row;
// 创建TableEnvironment
StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);
// 注册输入表
tableEnv.createTemporaryView("inputTable", inputDataStream, "intColumn");
// 执行聚合操作
Table resultTable = tableEnv.sqlQuery("SELECT COLLECT(intColumn) AS intArray FROM inputTable");
// 将结果转换为DataStream
DataStream<Row> resultDataStream = tableEnv.toAppendStream(resultTable, Row.class);
// 打印结果
resultDataStream.print();
import org.apache.flink.api.common.functions.AggregateFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.windowing.WindowFunction;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;
// 创建执行环境
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
// 创建输入数据流
DataStream<Tuple2<String, Integer>> inputDataStream = env.fromElements(
Tuple2.of("key", 1),
Tuple2.of("key", 2),
Tuple2.of("key", 3)
);
// 按照key进行分组,并在5秒的时间窗口内进行聚合
DataStream<Tuple2<String, Integer[]>> resultDataStream = inputDataStream
.keyBy(0)
.timeWindow(Time.seconds(5))
.aggregate(new IntArrayAggregator(), new IntArrayWindowFunction());
// 打印结果
resultDataStream.print();
// 定义聚合函数
public class IntArrayAggregator implements AggregateFunction<Tuple2<String, Integer>, List<Integer>, Integer[]> {
@Override
public List<Integer> createAccumulator() {
return new ArrayList<>();
}
@Override
public List<Integer> add(Tuple2<String, Integer> value, List<Integer> accumulator) {
accumulator.add(value.f1);
return accumulator;
}
@Override
public Integer[] getResult(List<Integer> accumulator) {
return accumulator.toArray(new Integer[0]);
}
@Override
public List<Integer> merge(List<Integer> a, List<Integer> b) {
a.addAll(b);
return a;
}
}
// 定义WindowFunction
public class IntArrayWindowFunction implements WindowFunction<Integer[], Tuple2<String, Integer[]>, String, TimeWindow> {
@Override
public void apply(String key, TimeWindow window, Iterable<Integer[]> input, Collector<Tuple2<String, Integer[]>> out) {
Integer[] result = input.iterator().next();
out.collect(Tuple2.of(key, result));
}
}
以上是两种在Flink中将int列聚合到array<int>的方法。这些方法可以根据具体的业务需求进行调整和扩展。
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