redis07

1 <dependency>
2     <groupId>redis.clients</groupId>
3     <artifactId>jedis</artifactId>
4 </dependency>

 1 public class RedisUtil {
 2 
 3     private JedisPool jedisPool;
 4 
 5     public void initPool(String host,int port ,int database){
 6         JedisPoolConfig poolConfig = new JedisPoolConfig();
 7         poolConfig.setMaxTotal(200);
 8         poolConfig.setMaxIdle(30);
 9         poolConfig.setBlockWhenExhausted(true);
10         poolConfig.setMaxWaitMillis(10*1000);
11         poolConfig.setTestOnBorrow(true);
12         jedisPool=new JedisPool(poolConfig,host,port,20*1000);
13     }
14 
15     public Jedis getJedis(){
16         Jedis jedis = jedisPool.getResource();
17         return jedis;
18     }
19 
20 }

 1 @Configuration
 2 public class RedisConfig {
 3     //读取配置文件中的redis的ip地址
 4     @Value("${spring.redis.host:disabled}")
 5     private String host;
 6     @Value("${spring.redis.port:0}")
 7     private int port ;
 8     @Value("${spring.redis.database:0}")
 9     private int database;
10     @Bean
11     public RedisUtil getRedisUtil(){
12         if(host.equals("disabled")){
13             return null;
14         }
15         RedisUtil redisUtil=new RedisUtil();
16         redisUtil.initPool(host,port,database);
17         return redisUtil;
18     }
19 }

spring.redis.host=192.168.239.139

spring.redis.port=6379

spring.redis.database=0

 1  @Override
 2     public PmsSkuInfo getSkuById(String skuId) {
 3 
 4         PmsSkuInfo pmsSkuInfo = new PmsSkuInfo();
 5 
 6 
 7         //连接缓存，查询缓存
 8         Jedis jedis = redisUtil.getJedis();
 9 
10 
11         //没有缓存，查询mysql
12         String skuKey = "sku:"+skuId+":info";
13         String skuJson = jedis.get(skuKey);
14 
15         if (StringUtils.isNotBlank(skuJson)){
16             pmsSkuInfo = JSON.parseObject(skuJson, PmsSkuInfo.class);
17         }else {
18 
19             //设置分布式锁
20             String token = UUID.randomUUID().toString();
21             String OK = jedis.set("sku:" + skuId + ":lock", token, "nx", "px", 10*1000);
22             if (StringUtils.isNotBlank(OK)&&OK.equals("OK")){
23                 //设置成功，有权在10s内访问数据库
24                 pmsSkuInfo = getSkuByIdFromDb(skuId);
25 
26                 try {
27                     Thread.sleep(2000);
28                 } catch (InterruptedException e) {
29                     e.printStackTrace();
30                 }
31 
32                 if (pmsSkuInfo != null){
33                     //mysql存入redis
34                     jedis.set("sku:"+skuId+":info",JSON.toJSONString(pmsSkuInfo));
35                 }else {
　　　　　　　　　　　　　　//数据库不存在该sku
36                     //防止缓存穿透,值设为空字符串或null
37                     jedis.setex("sku:"+skuId+":info",60*3,JSON.toJSONString(""));
38                 }
39 
40                 String lockToken = jedis.get("sku:" + skuId + ":lock");
41                 if(StringUtils.isNotBlank(lockToken)&&lockToken.equals(token)){  //用token确认删除的是自己的锁
42 
43                     //在访问mysql后，将mysql的分布式锁删除
44                     jedis.del("sku:" + skuId + ":lock");
45 
46                 }
47 
48             }else {
49                 //设置失败，自旋（该线程在睡眠几秒后，重新尝试本方法）
50                 return  getSkuById(skuId);
51             }
52 
53         }
54         jedis.close();
55 
56         return pmsSkuInfo;
57 
58     }

1                 //设置失败，自旋（该线程在睡眠几秒后，重新尝试本方法）
2                 try {
3                     Thread.sleep(3000);
4                 } catch (InterruptedException e) {
5                     e.printStackTrace();
6                 }
7                 
8                 getSkuById(skuId);