Java：封裝 Redis 工具類

首先是一個定義 Redis 的 Key 接口類，記錄 key 值(前綴）與緩存的時間：

public interface KeyPrefix {    
    public int expireSeconds();

    public String getPrefix();  
}

而後定義 Redis的工具類：

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.alibaba.fastjson.JSON;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.ScanParams;
import redis.clients.jedis.ScanResult;

@Service
public class RedisService {

    @Autowired
    JedisPool jedisPool;

    /**
     * 獲取單個對象
     * */
    public <T> T get(KeyPrefix prefix, String key,  Class<T> clazz) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
             //生成真正的key
             String realKey  = prefix.getPrefix() + key;
             String  str = jedis.get(realKey);
             T t =  stringToBean(str, clazz);
             return t;
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 設置對象
     * */
    public <T> boolean set(KeyPrefix prefix, String key,  T value) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
             String str = beanToString(value);
             if(str == null || str.length() <= 0) {
                 return false;
             }
            //生成真正的key
             String realKey  = prefix.getPrefix() + key;
             int seconds =  prefix.expireSeconds();
             if(seconds <= 0) {
                 jedis.set(realKey, str);
             }else {
                 jedis.setex(realKey, seconds, str);
             }
             return true;
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 判斷key是否存在
     * */
    public <T> boolean exists(KeyPrefix prefix, String key) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
            //生成真正的key
             String realKey  = prefix.getPrefix() + key;
            return  jedis.exists(realKey);
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 刪除
     * */
    public boolean delete(KeyPrefix prefix, String key) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
            //生成真正的key
            String realKey  = prefix.getPrefix() + key;
            long ret =  jedis.del(realKey);
            return ret > 0;
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 增長值
     * */
    public <T> Long incr(KeyPrefix prefix, String key) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
            //生成真正的key
             String realKey  = prefix.getPrefix() + key;
            return  jedis.incr(realKey);
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 減小值
     * */
    public <T> Long decr(KeyPrefix prefix, String key) {
         Jedis jedis = null;
         try {
             jedis =  jedisPool.getResource();
            //生成真正的key
             String realKey  = prefix.getPrefix() + key;
            return  jedis.decr(realKey);
         }finally {
              returnToPool(jedis);
         }
    }

    /**
     * 刪除值
     * */
    public boolean delete(KeyPrefix prefix) {
        if(prefix == null) {
            return false;
        }
        List<String> keys = scanKeys(prefix.getPrefix());
        if(keys==null || keys.size() <= 0) {
            return true;
        }
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            jedis.del(keys.toArray(new String[0]));
            return true;
        } catch (final Exception e) {
            e.printStackTrace();
            return false;
        } finally {
            if(jedis != null) {
                jedis.close();
            }
        }
    }

    public List<String> scanKeys(String key) {
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            List<String> keys = new ArrayList<String>();
            String cursor = "0";
            ScanParams sp = new ScanParams();
            sp.match("*"+key+"*");
            sp.count(100);
            do{
                ScanResult<String> ret = jedis.scan(cursor, 

sp);
                List<String> result = ret.getResult();
                if(result!=null && result.size() > 0){
                    keys.addAll(result);
                }
                //再處理cursor
                cursor = ret.getStringCursor();
            }while(!cursor.equals("0"));
            return keys;
        } finally {
            if (jedis != null) {
                jedis.close();
            }
        }
    }

    public static <T> String beanToString(T value) {
        if(value == null) {
            return null;
        }
        Class<?> clazz = value.getClass();
        if(clazz == int.class || clazz == Integer.class) {
             return ""+value;
        }else if(clazz == String.class) {
             return (String)value;
        }else if(clazz == long.class || clazz == Long.class) {
            return ""+value;
        }else {
            return JSON.toJSONString(value);
        }
    }

    @SuppressWarnings("unchecked")
    public static <T> T stringToBean(String str, Class<T> clazz) {
        if(str == null || str.length() <= 0 || clazz == null) {
             return null;
        }
        if(clazz == int.class || clazz == Integer.class) {
             return (T)Integer.valueOf(str);
        }else if(clazz == String.class) {
             return (T)str;
        }else if(clazz == long.class || clazz == Long.class) {
            return  (T)Long.valueOf(str);
        }else {
            return JSON.toJavaObject(JSON.parseObject(str), clazz);
        }
    }

    private void returnToPool(Jedis jedis) {
         if(jedis != null) {
             jedis.close();
         }
    }

}