Redisson基本用法

1.  Redisson

Redisson是Redis官方推荐的Java版的Redis客户端。它提供的功能非常多，也非常强大，此处我们只用它的分布式锁功能。

https://github.com/redisson/redisson

1.1.  基本用法

1 
2    org.redisson
3    redisson
4    3.11.1
5 

1.2.  Distributed locks and synchronizers

RedissonClient中提供了好多种锁，还有其它很多实用的方法

1.2.1.  Lock

默认，非公平锁

最简洁的一种方法

指定超时时间 

异步

1.2.2  Fair Lock 

1.2.3  MultiLock

1.2.4  RedLock

1.3.  示例

pom.xml

 1 
 2 
 4     4.0.0
 5     
 6         org.springframework.boot
 7         spring-boot-starter-parent
 8         2.1.6.RELEASE
 9          
10     
11     com.cjs.example
12     cjs-redisson-example
13     0.0.1-SNAPSHOT
14     cjs-redisson-example
15 
16     
17         1.8
18     
19 
20     
21         
22             org.springframework.boot
23             spring-boot-starter-data-jpa
24         
25         
26             org.springframework.boot
27             spring-boot-starter-data-redis
28         
29         
30             org.springframework.boot
31             spring-boot-starter-web
32         
33 
34         
35         
36             org.redisson
37             redisson
38             3.11.1
39         
40 
41 
42         
43             org.apache.commons
44             commons-lang3
45             3.9
46         
47         
48             com.alibaba
49             fastjson
50             1.2.58
51         
52         
53             org.apache.commons
54             commons-pool2
55             2.6.2
56         
57 
58         
59             mysql
60             mysql-connector-java
61             runtime
62         
63         
64             org.projectlombok
65             lombok
66             true
67         
68     
69 
70     
71         
72             
73                 org.springframework.boot
74                 spring-boot-maven-plugin
75             
76         
77     
78 
79 

application.yml

 1 server:
 2   port: 8080
 3 spring:
 4   application:
 5     name: cjs-redisson-example
 6   redis:
 7     cluster:
 8       nodes: 10.0.29.30:6379, 10.0.29.95:6379, 10.0.29.205:6379
 9     lettuce:
10       pool:
11         min-idle: 0
12         max-idle: 8
13         max-active: 20
14   datasource:
15     url: jdbc:mysql://127.0.0.1:3306/test
16     username: root
17     password: 123456
18     driver-class-name: com.mysql.cj.jdbc.Driver
19     type: com.zaxxer.hikari.HikariDataSource

RedissonConfig.java

 1 package com.cjs.example.lock.config;
 2 
 3 import org.redisson.Redisson;
 4 import org.redisson.api.RedissonClient;
 5 import org.redisson.config.Config;
 6 import org.springframework.context.annotation.Bean;
 7 import org.springframework.context.annotation.Configuration;
 8 
 9 /**
10  * @author ChengJianSheng
11  * @date 2019-07-26
12  */
13 @Configuration
14 public class RedissonConfig {
15 
16     @Bean
17     public RedissonClient redissonClient() {
18         Config config = new Config();
19         config.useClusterServers()
20                 .setScanInterval(2000)
21                 .addNodeAddress("redis://10.0.29.30:6379", "redis://10.0.29.95:6379")
22                 .addNodeAddress("redis://10.0.29.205:6379");
23 
24         RedissonClient redisson = Redisson.create(config);
25 
26         return redisson;
27     }
28 
29 }

CourseServiceImpl.java 

  1 package com.cjs.example.lock.service.impl;
  2 
  3 import com.alibaba.fastjson.JSON;
  4 import com.cjs.example.lock.constant.RedisKeyPrefixConstant;
  5 import com.cjs.example.lock.model.CourseModel;
  6 import com.cjs.example.lock.model.CourseRecordModel;
  7 import com.cjs.example.lock.repository.CourseRecordRepository;
  8 import com.cjs.example.lock.repository.CourseRepository;
  9 import com.cjs.example.lock.service.CourseService;
 10 import lombok.extern.slf4j.Slf4j;
 11 import org.apache.commons.lang3.StringUtils;
 12 import org.redisson.api.RLock;
 13 import org.redisson.api.RedissonClient;
 14 import org.springframework.beans.factory.annotation.Autowired;
 15 import org.springframework.data.redis.core.HashOperations;
 16 import org.springframework.data.redis.core.StringRedisTemplate;
 17 import org.springframework.stereotype.Service;
 18 
 19 import java.util.concurrent.TimeUnit;
 20 
 21 /**
 22  * @author ChengJianSheng
 23  * @date 2019-07-26
 24  */
 25 @Slf4j
 26 @Service
 27 public class CourseServiceImpl implements CourseService {
 28 
 29     @Autowired
 30     private CourseRepository courseRepository;
 31     @Autowired
 32     private CourseRecordRepository courseRecordRepository;
 33     @Autowired
 34     private StringRedisTemplate stringRedisTemplate;
 35     @Autowired
 36     private RedissonClient redissonClient;
 37 
 38     @Override
 39     public CourseModel getById(Integer courseId) {
 40 
 41         CourseModel courseModel = null;
 42 
 43         HashOperations hashOperations = stringRedisTemplate.opsForHash();
 44 
 45         String value = hashOperations.get(RedisKeyPrefixConstant.COURSE, String.valueOf(courseId));
 46 
 47         if (StringUtils.isBlank(value)) {
 48             String lockKey = RedisKeyPrefixConstant.LOCK_COURSE + courseId;
 49             RLock lock = redissonClient.getLock(lockKey);
 50             try {
 51                 boolean res = lock.tryLock(10, TimeUnit.SECONDS);
 52                 if (res) {
 53                     value = hashOperations.get(RedisKeyPrefixConstant.COURSE, String.valueOf(courseId));
 54                     if (StringUtils.isBlank(value)) {
 55                         log.info("从数据库中读取");
 56                         courseModel = courseRepository.findById(courseId).orElse(null);
 57                         hashOperations.put(RedisKeyPrefixConstant.COURSE, String.valueOf(courseId), JSON.toJSONString(courseModel));
 58                     }
 59                 }
 60             } catch (InterruptedException e) {
 61                 e.printStackTrace();
 62             } finally {
 63                 lock.unlock();
 64             }
 65         } else {
 66             log.info("从缓存中读取");
 67             courseModel = JSON.parseObject(value, CourseModel.class);
 68         }
 69 
 70         return courseModel;
 71     }
 72 
 73     @Override
 74     public void upload(Integer userId, Integer courseId, Integer studyProcess) {
 75 
 76         HashOperations hashOperations = stringRedisTemplate.opsForHash();
 77 
 78         String cacheKey = RedisKeyPrefixConstant.COURSE_PROGRESS + ":" + userId;
 79         String cacheValue = hashOperations.get(cacheKey, String.valueOf(courseId));
 80         if (StringUtils.isNotBlank(cacheValue) && studyProcess  Integer.valueOf(cacheValue)) {
 93                 CourseRecordModel model = new CourseRecordModel();
 94                 model.setUserId(userId);
 95                 model.setCourseId(courseId);
 96                 model.setStudyProcess(studyProcess);
 97                 courseRecordRepository.save(model);
 98                 hashOperations.put(cacheKey, String.valueOf(courseId), String.valueOf(studyProcess));
 99             }
100 
101         } catch (Exception ex) {
102             log.error("获取所超时！", ex);
103         } finally {
104             lock.unlock();
105         }
106 
107     }
108 }

StockServiceImpl.java

 1 package com.cjs.example.lock.service.impl;
 2 
 3 import com.cjs.example.lock.constant.RedisKeyPrefixConstant;
 4 import com.cjs.example.lock.service.StockService;
 5 import org.apache.commons.lang3.StringUtils;
 6 import org.springframework.beans.factory.annotation.Autowired;
 7 import org.springframework.data.redis.core.HashOperations;
 8 import org.springframework.data.redis.core.StringRedisTemplate;
 9 import org.springframework.stereotype.Service;
10 
11 /**
12  * @author ChengJianSheng
13  * @date 2019-07-26
14  */
15 @Service
16 public class StockServiceImpl implements StockService {
17 
18     @Autowired
19     private StringRedisTemplate stringRedisTemplate;
20 
21     @Override
22     public int getByProduct(Integer productId) {
23         HashOperations hashOperations = stringRedisTemplate.opsForHash();
24         String value = hashOperations.get(RedisKeyPrefixConstant.STOCK, String.valueOf(productId));
25         if (StringUtils.isBlank(value)) {
26             return 0;
27         }
28         return Integer.valueOf(value);
29     }
30 
31     @Override
32     public boolean decrease(Integer productId) {
33         int stock = getByProduct(productId);
34         if (stock