Java:封裝 Redis 工具類
阿新 • • 發佈:2019-01-11
首先是一個定義 Redis 的 Key 介面類,記錄 key 值(字首)與快取的時間:
public interface KeyPrefix {
public int expireSeconds();
public String getPrefix();
}
然後定義 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; /** * 獲取單個物件 * */ 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); } } /** * 設定物件 * */ 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); } } /** * 增加值 * */ 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); } } /** * 減少值 * */ 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(); } } }