在SSM项目中使用redis实现数据缓存

墨蓝 2022-04-18 02:08 420阅读 0赞

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

<context:property-placeholder location="classpath: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<BaseDict> selectBaseDictListByCode(String code){
    		String key = DICTLISTKEY;
    		List<BaseDict> 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;
    	}