zk实现分布式锁

1. maven依赖

    <dependencies>
       <dependency>
           <groupId>org.apache.zookeeper</groupId>
           <artifactId>zookeeper</artifactId>
           <version>3.6.2</version>
           <exclusions>
               <exclusion>
                   <artifactId>slf4j-log4j12</artifactId>
                   <groupId>org.slf4j</groupId>
               </exclusion>
           </exclusions>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter</artifactId>
       </dependency>
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
       </dependency>
   
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-jdbc</artifactId>
       </dependency>
   
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-web</artifactId>
       </dependency>
   
       <dependency>
           <groupId>org.projectlombok</groupId>
           <artifactId>lombok</artifactId>
           <optional>true</optional>
       </dependency>
       <dependency>
           <groupId>org.apache.commons</groupId>
           <artifactId>commons-lang3</artifactId>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-test</artifactId>
           <scope>test</scope>
       </dependency>
       <dependency>
           <groupId>com.101tec</groupId>
           <artifactId>zkclient</artifactId>
           <version>0.10</version>
           <exclusions>
               <exclusion>
                   <artifactId>zookeeper</artifactId>
                   <groupId>org.apache.zookeeper</groupId>
               </exclusion>
           </exclusions>
       </dependency>
       <!-- https://mvnrepository.com/artifact/org.apache.curator/curator-framework -->
       <dependency>
           <groupId>org.apache.curator</groupId>
           <artifactId>curator-framework</artifactId>
           <version>5.1.0</version>
           <exclusions>
               <exclusion>
                   <artifactId>zookeeper</artifactId>
                   <groupId>org.apache.zookeeper</groupId>
               </exclusion>
           </exclusions>
       </dependency>
       <!-- https://mvnrepository.com/artifact/org.apache.curator/curator-recipes -->
       <dependency>
           <groupId>org.apache.curator</groupId>
           <artifactId>curator-recipes</artifactId>
           <version>5.1.0</version>
       </dependency>
       <dependency>
           <groupId>junit</groupId>
           <artifactId>junit</artifactId>
           <version>4.12</version>
           <scope>compile</scope>
       </dependency>
   </dependencies>
   

2. 数据库创建一个test模拟商品id与库存
3. 实现代码

   package cn.jaminye.zklock.controller;
   
   import org.apache.curator.framework.CuratorFramework;
   import org.apache.curator.framework.CuratorFrameworkFactory;
   import org.apache.curator.framework.recipes.locks.InterProcessMutex;
   import org.apache.curator.retry.RetryNTimes;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.jdbc.core.JdbcTemplate;
   import org.springframework.stereotype.Controller;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.ResponseBody;
   
   import javax.servlet.http.HttpServletRequest;
   import java.util.concurrent.TimeUnit;
   
   /**
    * @author Jamin
    * @date 2020/11/30 10:36
    */
   @Controller
   public class ZkLockController {
       static CuratorFramework curatorFramework;
       //重试3次每次1秒钟
       static RetryNTimes retryPolicy = new RetryNTimes(3, 1000);
   
       static {
           //建立与zk的连接
           curatorFramework = CuratorFrameworkFactory.builder().connectString("192.168.150.120:2181").sessionTimeoutMs(100000)
                   .connectionTimeoutMs(100000).retryPolicy(retryPolicy).build();
           curatorFramework.start();
       }
   
       @Autowired
       JdbcTemplate jdbcTemplate;
   
       @ResponseBody
       @RequestMapping("reduceInventory")
       public String reduceInventory() {
           //不可重入独占锁
           // InterProcessSemaphoreMutex interProcessSemaphoreMutex = new InterProcessSemaphoreMutex(curatorFramework, "/lock");
           //可重入独占锁
           InterProcessMutex lock = new InterProcessMutex(curatorFramework, "/lock");
           try {
               //获得锁
               if (lock.acquire(5, TimeUnit.SECONDS)) {
                   String sql = "select counts from test";
                   //查库存
                   int i = jdbcTemplate.queryForObject(sql, Integer.class).intValue();
                   if (i > 0) {
                       System.out.println(i);
                       //减库存
                       String sql1 = "update test set counts=counts-1 where id=1";
                       jdbcTemplate.update(sql1);
                       System.out.println("减少库存");
                   }
                   //释放锁
                   lock.release();
               } else {
                   return "请稍后再试";
               }
           } catch (Exception e) {
               System.out.println("获取锁失败");
               return "failed";
           }
           return "success";
       }
   }