1.         <dependency>
    2.             <groupId>org.apache.zookeeper</groupId>
    3.             <artifactId>zookeeper</artifactId>
    4.             <version>3.7.0</version>
    5.         </dependency>
    1. @Slf4j
    2. public class ZkLock implements AutoCloseable, Watcher {
    4.     private final ZooKeeper zk;
    5.     private String znode;
    7.     public ZkLock(String zkServers) throws Exception {
    8.         zk = new ZooKeeper(zkServers, 600000, this);
    9.     }
    11.     public boolean getLock(String businessCode) {
    12.         try {
    13.             // 创建业务 根节点
    14.             Stat stat = zk.exists("/" + businessCode, false);
    15.             if (stat == null) {
    16.                 zk.create("/" + businessCode, businessCode.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    17.             }
    18.             // 创建瞬时有序节点  /order/order_000000001
    19.             znode = zk.create("/" + businessCode + "/" + businessCode + "_", businessCode.getBytes(),
    20.                     ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
    21.             // 获取所有子节点
    22.             List<String> childrenNodes = zk.getChildren("/" + businessCode, false);
    23.             // 子节点排序
    24.             Collections.sort(childrenNodes);
    25.             // 获取序号最小的（第一个）节点
    26.             String firstNode = childrenNodes.get(0);
    27.             // 判断是否是第一个节点
    28.             if (znode.endsWith(firstNode)) {
    29.                 return true;
    30.             }
    31.             // 获取第一个节点的前一个节点
    32.             String lastNode = firstNode;
    33.             for (String node : childrenNodes) {
    34.                 if (znode.endsWith(node)) {
    35.                     zk.exists("/" + businessCode + "/" + lastNode, true);
    36.                     break;
    37.                 } else {
    38.                     lastNode = node;
    39.                 }
    40.             }
    41.             synchronized (this) {
    42.                 wait();
    43.             }
    44.             return true;
    45.         } catch (KeeperException | InterruptedException e) {
    46.             e.printStackTrace();
    47.         }
    48.         return false;
    49.     }
    51.     @Override
    52.     public void close() throws Exception {
    53.         zk.delete(znode, -1);
    54.         zk.close();
    55.         log.info("zk 释放了锁");
    56.     }
    58.     @Override
    59.     public void process(WatchedEvent watchedEvent) {
    60.         if (watchedEvent.getType() == Event.EventType.NodeDeleted) {
    61.             synchronized (this) {
    62.                 notify();
    63.             }
    64.         }
    65.     }
    66. }
    1. @Slf4j
    2. @RestController
    3. public class ZkLockController {
    5.     @RequestMapping("/zklock")
    6.     public String zookeeperLock() {
    7.         log.info("进入了方法");
    8.         try (ZkLock zkLock = new ZkLock("localhost:2181")){
    9.             if (zkLock.getLock("order")) {
    10.                 log.info("获取锁成功");
    11.                 Thread.sleep(5000);
    12.             }
    13.         } catch (Exception e) {
    14.             e.printStackTrace();
    15.         }
    16.         log.info("结束了方法");
    17.         return "结束了方法";
    18.     }
    20. }