如何在十亿用户中检查某个用户名是否存在？

import org.redisson.Redisson;  
import org.redisson.api.RedissonClient;  
import org.redisson.config.Config;  
import org.redisson.api.RMap;  
  
public class UserExistenceChecker {  
  
    // Redis hash map name to store user information  
    private static final String USER_HASH_NAME = "users";  
  
    public static void main(String[] args) {  
        // Create a Redisson client  
        RedissonClient redisson = createRedissonClient();  
  
        // Retrieve the hash map to store user information  
        RMap<String, String> users = redisson.getMap(USER_HASH_NAME);  
  
        // Add a user to the hash map  
        users.put("user123", "someUserInfo"); // Here "someUserInfo" could be a JSON string, UUID, etc.  
  
        // Check if a user exists  
        boolean exists = users.containsKey("user123");  
        System.out.println("User 'user123' exists? " + exists);  
  
        // Check for a non-existent user  
        exists = users.containsKey("user456");  
        System.out.println("User 'user456' exists? " + exists);  
  
        // Shutdown the Redisson client  
        redisson.shutdown();  
    }  
  
    // Helper method to create a Redisson client  
    private static RedissonClient createRedissonClient() {  
        Config config = new Config();  
        config.useSingleServer()  
                .setAddress("redis://127.0.0.1:6379") // Adjust to your Redis address  
                .setPassword("yourpassword"); // Provide your Redis password if any  
  
        return Redisson.create(config);  
    }  
}

import org.redisson.Redisson;
import org.redisson.api.RBloomFilter;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;

public class UserExistenceChecker {

    // Name of the Bloom Filter in Redis
    private static final String BLOOM_FILTER_NAME = "user_existence_filter";

    public static void main(String[] args) {
        // Create a Redisson client
        RedissonClient redisson = createRedissonClient();

        // Retrieve or create a Bloom Filter instance
        // Expected number of elements and false positive probability are parameters
        RBloomFilter<String> bloomFilter = redisson.getBloomFilter(BLOOM_FILTER_NAME);
        bloomFilter.tryInit(100000L, 0.001); // Initialize the Bloom Filter with expected elements and false positive rate

        // Add a user to the Bloom Filter
        bloomFilter.add("user123");

        // Check if a user exists
        boolean exists = bloomFilter.contains("user123"); // Should return true
        System.out.println("User 'user123' exists? " + exists);

        // Check for a non-existent user (might falsely report as true due to Bloom Filter's nature)
        exists = bloomFilter.contains("user456"); // Assuming not added, should ideally return false, but could be a false positive
        System.out.println("User 'user456' exists? " + exists);

        // Shutdown the Redisson client
        redisson.shutdown();
    }

    // Helper method to create a Redisson client
    private static RedissonClient createRedissonClient() {
        Config config = new Config();
        config.useSingleServer()
                .setAddress("redis://127.0.0.1:6379"); // Adjust to your Redis address
//                .setPassword("yourpassword"); // Provide your Redis password if any

        return Redisson.create(config);
    }
}