各位大佬，请教个问题，刚开始用flink1.17.1版本，写入到测试环境自建的kafka，数据能写？

可以的，以下是简单的示例代码：

import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.sink.SinkFunction;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer;

public class KafkaSinkExample {

public static void main(String[] args) throws Exception {
// 获取 Flink 运行环境
StreamExecutionEnvironment environment = StreamExecutionEnvironment.getExecutionEnvironment();

// 读取数据源
DataStream<String> input = environment.socketTextStream("localhost", 9090);

// 写入 Kafka
input.addSink(new FlinkKafkaProducer<>(
    "localhost:9092",
    "my-topic",
    (String value) -> new ProducerRecord<>("my-topic", value),
    new FlinkKafkaProducer.FlinkKafkaSerializationSchemaWrapper<String>(
        new SimpleStringSchema())));

// 启动 Flink 程序
environment.execute();

}
}
运行该示例，Flink 程序会从本地 localhost:9090 端口读取数据，并将数据写入到 Kafka 的 my-topic 主题中。