添加单例Kafka生产者:尝试读取或写入受保护的内存

public class KafkaProducerSingleton {
    private static KafkaProducer<String, String> producer;

    private KafkaProducerSingleton() {
        // 私有构造函数，防止外部实例化
    }

    public static synchronized KafkaProducer<String, String> getInstance() {
        if (producer == null) {
            Properties props = new Properties();
            props.put("bootstrap.servers", "kafka-server1:9092,kafka-server2:9092");
            props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
            props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
            producer = new KafkaProducer<>(props);
        }
        return producer;
    }
}