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 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 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);    }}