How to handle null response of get command using lettuce reactive api - redis

Question

I'm using lettuce reactive api to query redis, and need to handle the situation redis doesn't has the key. But it seems that it dosen't call the function of subscribe when the key doesn't exist
I want to query redis and then print the result,
if the result exist, it should print "result received:{result}"
and if the result doesn't exist, it should print "result received:null".
RedisURI redisURI = RedisURI.builder().withHost("10.203.0.114").withPort(6379).withPassword("123456").build();
RedisClient client = RedisClient.create(redisURI);
StatefulRedisConnection<String,String> connection = client.connect();
RedisStringReactiveCommands<String,String> reactive = connection.reactive();
reactive.get("hello").onErrorReturn("error").subscribe(res->{
System.out.println("result receive:"+res);
},Throwable::printStackTrace);
reactive.get("hell").doOnError(throwable -> {
System.out.println("do on error");
throwable.printStackTrace();
}).subscribe(r->{
System.out.println("result receive:"+r);
});
redis has the key: hello and it's value is world.
I expect the output of first get call should be "result receive:world" and actual output is the same with my expectation.
The output of second call should be "result receive:null",but nothing is printed actually
Solution:I found lettuce use project reactor api and its api behaviour is different from rxjava.It should use switchIfEmpty to handle null response
reactive.get("hell").switchIfEmpty(Mono.just("")).doOnError(throwable -> {
System.out.println("do on error");
throwable.printStackTrace();
}).subscribe(r->{
System.out.println("result receive:"+r);
});