流计算怎么创建

import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.api.common.functions.MapFunction;

public class StreamingJob {
    public static void main(String[] args) throws Exception {
        // 创建流处理环境
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 从Kafka读取数据流
        DataStream<String> stream = env.addSource(new FlinkKafkaConsumer<>("topic", new SimpleStringSchema(), properties));

        // 数据处理逻辑
        DataStream<Integer> counts = stream
            .map(new MapFunction<String, Integer>() {
                @Override
                public Integer map(String value) {
                    return value.length();
                }
            });

        // 输出结果到控制台
        counts.print();

        // 执行流处理程序
        env.execute("Flink Streaming Java API Skeleton");
    }
}