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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。

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

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    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         
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      48             
      
       com.alibaba
      49             
      
       fastjson
      50             
      
       1.2.58
      51         
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      53             
      
       org.apache.commons
      54             
      
       commons-pool2
      55             
      
       2.6.2
      56         
     57 58         
     
      59             
      
       mysql
      60             
      
       mysql-connector-java
      61             
      
       runtime
      62         
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      64             
      
       org.projectlombok
      65             
      
       lombok
      66             
      
       true
      67         
     68     
    69 70     
    
     71         
     
      72             
      
       73                 
       
        org.springframework.boot
       74                 
       
        spring-boot-maven-plugin
       75             
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     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: 012         max-idle: 813         max-active: 2014   datasource:15     url: jdbc:mysql://127.0.0.1:3306/test16     username: root17     password: 12345618     driver-class-name: com.mysql.cj.jdbc.Driver19     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 ChengJianSheng11  * @date 2019-07-2612  */13 @Configuration14 public class RedissonConfig {15 16     @Bean17     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)) { 81             return; 82         } 83  84         String lockKey = "upload:" + userId + ":" + courseId; 85  86         RLock lock = redissonClient.getLock(lockKey); 87  88         try { 89             lock.lock(10, TimeUnit.SECONDS); 90  91             cacheValue = hashOperations.get(cacheKey, String.valueOf(courseId)); 92             if (StringUtils.isBlank(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 ChengJianSheng13  * @date 2019-07-2614  */15 @Service16 public class StockServiceImpl implements StockService {17 18     @Autowired19     private StringRedisTemplate stringRedisTemplate;20 21     @Override22     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     @Override32     public boolean decrease(Integer productId) {33         int stock = getByProduct(productId);34         if (stock <= 0) {35             return false;36         }37         HashOperations
    
      hashOperations = stringRedisTemplate.opsForHash();38         hashOperations.put(RedisKeyPrefixConstant.STOCK, String.valueOf(productId), String.valueOf(stock - 1));39         return true;40     }41 }
    
   

OrderServiceImpl.java

1 package com.cjs.example.lock.service.impl; 2  3 import com.cjs.example.lock.model.OrderModel; 4 import com.cjs.example.lock.repository.OrderRepository; 5 import com.cjs.example.lock.service.OrderService; 6 import com.cjs.example.lock.service.StockService; 7 import lombok.extern.slf4j.Slf4j; 8 import org.redisson.api.RLock; 9 import org.redisson.api.RedissonClient;10 import org.springframework.beans.factory.annotation.Autowired;11 import org.springframework.stereotype.Service;12 13 import java.util.Date;14 import java.util.UUID;15 import java.util.concurrent.TimeUnit;16 17 /**18  * @author ChengJianSheng19  * @date 2019-07-3020  */21 @Slf4j22 @Service23 public class OrderServiceImpl implements OrderService {24 25     @Autowired26     private StockService stockService;27     @Autowired28     private OrderRepository orderRepository;29     @Autowired30     private RedissonClient redissonClient;31 32     /**33      * 乐观锁34      */35     @Override36     public String save(Integer userId, Integer productId) {37         int stock = stockService.getByProduct(productId);38         log.info("剩余库存：{}", stock);39         if (stock <= 0) {40             return null;41         }42 43         //  如果不加锁，必然超卖44 45         RLock lock = redissonClient.getLock("stock:" + productId);46 47         try {48             lock.lock(10, TimeUnit.SECONDS);49 50             String orderNo = UUID.randomUUID().toString().replace("-", "").toUpperCase();51 52             if (stockService.decrease(productId)) {53 54                 OrderModel orderModel = new OrderModel();55                 orderModel.setUserId(userId);56                 orderModel.setProductId(productId);57                 orderModel.setOrderNo(orderNo);58                 Date now = new Date();59                 orderModel.setCreateTime(now);60                 orderModel.setUpdateTime(now);61                 orderRepository.save(orderModel);62 63                 return orderNo;64             }65 66         } catch (Exception ex) {67             log.error("下单失败", ex);68         } finally {69             lock.unlock();70         }71 72         return null;73     }74 75 }

OrderModel.java

1 package com.cjs.example.lock.model; 2  3 import lombok.Data; 4  5 import javax.persistence.*; 6 import java.io.Serializable; 7 import java.util.Date; 8  9 /**10  * @author ChengJianSheng11  * @date 2019-07-3012  */13 @Data14 @Entity15 @Table(name = "t_order")16 public class OrderModel implements Serializable {17 18     @Id19     @GeneratedValue(strategy = GenerationType.IDENTITY)20     private Integer id;21 22     @Column(name = "order_no")23     private String orderNo;24 25     @Column(name = "product_id")26     private Integer productId;27 28     @Column(name = "user_id")29     private Integer userId;30 31     @Column(name = "create_time")32     private Date createTime;33 34     @Column(name = "update_time")35     private Date updateTime;36 } 

数据库脚本.sql

1 SET NAMES utf8mb4; 2 SET FOREIGN_KEY_CHECKS = 0; 3  4 -- ---------------------------- 5 -- Table structure for t_course 6 -- ---------------------------- 7 DROP TABLE IF EXISTS `t_course`; 8 CREATE TABLE `t_course` ( 9   `id` int(11) NOT NULL AUTO_INCREMENT,10   `course_name` varchar(64) NOT NULL,11   `course_type` tinyint(4) NOT NULL DEFAULT '1',12   `start_time` datetime NOT NULL,13   PRIMARY KEY (`id`)14 ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4;15 16 -- ----------------------------17 -- Table structure for t_order18 -- ----------------------------19 DROP TABLE IF EXISTS `t_order`;20 CREATE TABLE `t_order` (21   `id` int(11) NOT NULL AUTO_INCREMENT,22   `order_no` varchar(256) CHARACTER SET latin1 NOT NULL,23   `user_id` int(11) NOT NULL,24   `product_id` int(11) NOT NULL,25   `create_time` datetime NOT NULL,26   `update_time` datetime DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,27   PRIMARY KEY (`id`)28 ) ENGINE=InnoDB AUTO_INCREMENT=109 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;29 30 -- ----------------------------31 -- Table structure for t_user_course_record32 -- ----------------------------33 DROP TABLE IF EXISTS `t_user_course_record`;34 CREATE TABLE `t_user_course_record` (35   `id` int(11) NOT NULL AUTO_INCREMENT,36   `user_id` int(11) NOT NULL,37   `course_id` int(11) NOT NULL,38   `study_process` int(11) NOT NULL,39   PRIMARY KEY (`id`)40 ) ENGINE=InnoDB AUTO_INCREMENT=103 DEFAULT CHARSET=utf8mb4;41 42 SET FOREIGN_KEY_CHECKS = 1; 

1.4  工程结构

 

1.5  Redis集群创建

1.6  测试

测试/course/upload

测试/order/create

2.  Spring Integration

用法与Redisson类似

1 
   
    2     
    
     org.springframework.boot
    3     
    
     spring-boot-starter-integration
    4 
   5 
   
    6     
    
     org.springframework.integration
    7     
    
     spring-integration-redis
    8 
   

1 package com.kaishustory.base.conf; 2  3 import org.springframework.context.annotation.Bean; 4 import org.springframework.context.annotation.Configuration; 5 import org.springframework.data.redis.connection.RedisConnectionFactory; 6 import org.springframework.integration.redis.util.RedisLockRegistry; 7  8 /** 9  * @author ChengJianSheng10  * @date 2019-07-3011  */12 @Configuration13 public class RedisLockConfig {14 15     @Bean16     public RedisLockRegistry redisLockRegistry(RedisConnectionFactory redisConnectionFactory) {17         return new RedisLockRegistry(redisConnectionFactory, "asdf")18     }19 20 }

1 @Autowired 2 private RedisLockRegistry redisLockRegistry; 3  4 public void save(Integer userId) { 5  6     String lockKey = "order:" + userId; 7  8     Lock lock = redisLockRegistry.obtain(lockKey); 9     try {10         lock.lock();11 12         //todo13 14     } finally {15         lock.unlock();16     }17 18 }

3.  其它

 

来源：

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