import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ExpressionParser;
import org.springframework.expression.common.LiteralExpression;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.integration.annotation.InboundChannelAdapter;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.config.EnableIntegration;
KafkaProducerMessageHandler<String, String> handler =
new KafkaProducerMessageHandler<>(kafkaTemplate);
handler.setTopicExpression(new LiteralExpression(properties.getOutputTopic()));
+ final ExpressionParser parser = new SpelExpressionParser();
+ Expression expression = parser.parseExpression("headers['kafka_receivedMessageKey']");
+ handler.setMessageKeyExpression(expression);
return handler;
}