flink消费kafka的数据存到kafka java代码

以下是将Flink消费Kafka的数据存储到Kafka的Java代码示例：

import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer;
import org.apache.flink.streaming.util.serialization.KeyedSerializationSchemaWrapper;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;

import java.util.Properties;

public class FlinkKafkaExample {

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

        // 设置执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 设置Kafka Consumer的参数
        Properties consumerProps = new Properties();
        consumerProps.setProperty("bootstrap.servers", "localhost:9092");
        consumerProps.setProperty("group.id", "test-group");

        // 创建Kafka Consumer
        FlinkKafkaConsumer<String> kafkaConsumer = new FlinkKafkaConsumer<>("test-topic", new SimpleStringSchema(), consumerProps);

        // 添加Kafka Consumer数据源
        DataStream<String> stream = env.addSource(kafkaConsumer);

        // 对数据进行处理
        DataStream<String> processedStream = stream.map(str -> str.toUpperCase());

        // 设置Kafka Producer的参数
        Properties producerProps = new Properties();
        producerProps.setProperty("bootstrap.servers", "localhost:9092");

        // 创建Kafka Producer
        FlinkKafkaProducer<String> kafkaProducer = new FlinkKafkaProducer<>("output-topic", new KeyedSerializationSchemaWrapper<>(new SimpleStringSchema()), producerProps, FlinkKafkaProducer.Semantic.EXACTLY_ONCE);

        // 将处理后的数据写入Kafka
        processedStream.addSink(kafkaProducer);

        // 执行任务
        env.execute("Flink Kafka Example");
    }
}