<dependencies>  
    <!-- 其他依賴... -->  
    <dependency>  
        <groupId>redis.clients</groupId>  
        <artifactId>jedis</artifactId>  
        <version>3.7.0</version> 
    </dependency>  
</dependencies>

import redis.clients.jedis.Jedis;  
// 數(shù)據(jù)庫中的User表對應(yīng)的Java類  
class User {  
    private int id;  
    private String username;  
    private String email;  
    // 構(gòu)造器、getter和setter方法...  
}  
// Redis操作類  
class RedisCache {  
    private Jedis jedis;  
    public RedisCache(String host, int port) {  
        jedis = new Jedis(host, port);  
    }  
    // 緩存User數(shù)據(jù)  
    public void cacheUser(User user) {  
        String userIdKey = "user:id:" + user.getId();  
        String usernameKey = "user:username:" + user.getId();  
        jedis.set(userIdKey, String.valueOf(user.getId()));  
        jedis.set(usernameKey, user.getUsername());  
    }  
    // 根據(jù)ID獲取緩存中的User數(shù)據(jù)  
    public User getUserById(int id) {  
        String userIdKey = "user:id:" + id;  
        String usernameKey = "user:username:" + id;  
        String userId = jedis.get(userIdKey);  
        String username = jedis.get(usernameKey);  
        if (userId != null && username != null) {  
            User user = new User();  
            user.setId(Integer.parseInt(userId));  
            user.setUsername(username);  
            // 注意：這里我們沒有緩存email，所以需要從數(shù)據(jù)庫獲取或設(shè)為null  
            // 根據(jù)實(shí)際需求，你也可以選擇緩存email或其他字段  
            return user;  
        }  
        return null;  
    }  
    // 關(guān)閉連接  
    public void close() {  
        if (jedis != null) {  
            jedis.close();  
        }  
    }  
}  
// 主類，用于演示如何使用RedisCache  
public class RedisCacheExample {  
    public static void main(String[] args) {  
        RedisCache redisCache = new RedisCache("localhost", 6379);  
        // 假設(shè)這是從數(shù)據(jù)庫獲取的User對象  
        User userFromDatabase = new User();  
        userFromDatabase.setId(1);  
        userFromDatabase.setUsername("john_doe");  
        userFromDatabase.setEmail("john.doe@example.com");  
        // 將User對象緩存到Redis中  
        redisCache.cacheUser(userFromDatabase);  
        // 從Redis中根據(jù)ID獲取User對象  
        User cachedUser = redisCache.getUserById(1);  
        if (cachedUser != null) {  
            System.out.println("Cached User ID: " + cachedUser.getId());  
            System.out.println("Cached Username: " + cachedUser.getUsername());  
        } else {  
            System.out.println("User not found in cache");  
        }  
        // 關(guān)閉Redis連接  
        redisCache.close();  
    }  
}