在SSM项目中使用redis实现数据缓存

redis是一个key-value存储系统。和Memcached类似，它支持存储的value类型相对更多，包括string(字符串)、list(链表)、set(集合)、zset(sorted set --有序集合)和hash（哈希类型）。

redis的具体操作不详述，介绍一下redis在SSM项目中的使用

一、redis.properties配置文件

redis.hostname=127.0.0.1
redis.port=6379
redis.database=0
redis.pool.maxActive=600
redis.pool.maxIdle=300
redis.pool.maxWait=3000
redis.pool.testOnBorrow=true

二、spring文件加载redis.properties

三、redis连接池配置spring-redis.xml

四、JedisPoolWriper

import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

/**
 * 强指定redis的JedisPool接口构造函数，这样才能在centos成功创建jedispool
 * 
 * @author xiangze
 *
 */
public class JedisPoolWriper {
	private JedisPool jedisPool;

	public JedisPoolWriper(final JedisPoolConfig poolConfig, final String host,
			final int port) {
		try {
			jedisPool = new JedisPool(poolConfig, host, port);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public JedisPool getJedisPool() {
		return jedisPool;
	}

	public void setJedisPool(JedisPool jedisPool) {
		this.jedisPool = jedisPool;
	}

}

五、jedis工具栏JedisUtil

public class JedisUtil {
	/**
	 * 缓存生存时间
	 */
	private final int expire = 60000;
	/** 操作Key的方法 */
	public Keys KEYS;
	private JedisPool jedisPool;

	public JedisPool getJedisPool() {
		return jedisPool;
	}

	public void setJedisPool(JedisPoolWriper jedisPoolWriper) {
		this.jedisPool = jedisPoolWriper.getJedisPool();
	}

	public JedisPool getPool() {
		return jedisPool;
	}

	/**
	 * 从jedis连接池中获取获取jedis对象
	 * 
	 * @return
	 */
	public Jedis getJedis() {
		return jedisPool.getResource();
	}

	// *******************************************Keys*******************************************//
	public class Keys {

	
		/**
		 * 更改key
		 * 
		 * @param String
		 *            oldkey
		 * @param String
		 *            newkey
		 * @return 状态码
		 * */
		public String rename(String oldkey, String newkey) {
			return rename(SafeEncoder.encode(oldkey),
					SafeEncoder.encode(newkey));
		}

		/**
		 * 更改key,仅当新key不存在时才执行
		 * 
		 * @param String
		 *            oldkey
		 * @param String
		 *            newkey
		 * @return 状态码
		 * */
		public long renamenx(String oldkey, String newkey) {
			Jedis jedis = getJedis();
			long status = jedis.renamenx(oldkey, newkey);
			jedis.close();
			return status;
		}

		/**
		 * 更改key
		 * 
		 * @param String
		 *            oldkey
		 * @param String
		 *            newkey
		 * @return 状态码
		 * */
		public String rename(byte[] oldkey, byte[] newkey) {
			Jedis jedis = getJedis();
			String status = jedis.rename(oldkey, newkey);
			jedis.close();
			return status;
		}

		/**
		 * 设置key的过期时间，以秒为单位
		 * 
		 * @param String
		 *            key
		 * @param 时间
		 *            ,已秒为单位
		 * @return 影响的记录数
		 * */
		public long expired(String key, int seconds) {
			Jedis jedis = getJedis();
			long count = jedis.expire(key, seconds);
			jedis.close();
			return count;
		}
		/**
		 * 判断key是否存在
		 * 
		 * @param String
		 *            key
		 * @return boolean
		 * */
		public boolean exists(String key) {
			// ShardedJedis sjedis = getShardedJedis();
			Jedis sjedis = getJedis();
			boolean exis = sjedis.exists(key);
			sjedis.close();
			return exis;
		}

service层操作插入缓存

@Service
@Transactional
public class BaseDictServiceImpl implements BaseDictService {

	@Autowired
	private BaseDictMapper baseDictMapper;
	
	@Autowired
	private JedisUtil.Keys jedisKeys;
	
	@Autowired
	private JedisUtil.Strings jedisStrings;
	
	private static String DICTLISTKEY ="dictlist";//多个传入不同的code方法   key会相同,后面的value覆盖前面的redis里value
	
	public List selectBaseDictListByCode(String code){
		String key = DICTLISTKEY;
		List dictList =null;
		ObjectMapper mapper=new ObjectMapper();
		if(!jedisKeys.exists(key)) {
			dictList = baseDictMapper.selectBaseDictListByCode(code);
			String jsonString = null;
			try {
				jsonString =mapper.writeValueAsString(dictList);
			} catch (JsonProcessingException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			
			}
			jedisStrings.set(key, jsonString);
		}else {
			String jsonString = jedisStrings.get(key);
			JavaType javaType=mapper.getTypeFactory().constructParametricType(ArrayList.class, BaseDict.class);
			try {
				dictList = mapper.readValue(jsonString, javaType);
			} catch (JsonParseException e) {
				e.printStackTrace();
			} catch (JsonMappingException e) {
		
				e.printStackTrace();
			} catch (IOException e) {

				e.printStackTrace();
			}
		}
		return dictList;
	}