此 demo 主要演示了如何使用 Spring Boot 集成 Zookeeper 结合AOP实现分布式锁。
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>spring-boot-demo-zookeeper</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-boot-demo-zookeeper</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>com.xkcoding</groupId>
<artifactId>spring-boot-demo</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<!-- curator 版本4.1.0 对应 zookeeper 版本 3.5.x -->
<!-- curator 与 zookeeper 版本对应关系：https://curator.apache.org/zk-compatibility.html -->
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-recipes</artifactId>
<version>4.1.0</version>
</dependency>
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
<build>
<finalName>spring-boot-demo-zookeeper</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>/**
* <p>
* Zookeeper 配置项
* </p>
*
* @author yangkai.shen
* @date Created in 2018-12-27 14:47
*/
@Data
@ConfigurationProperties(prefix = "zk")
public class ZkProps {
/**
* 连接地址
*/
private String url;
/**
* 超时时间(毫秒)，默认1000
*/
private int timeout = 1000;
/**
* 重试次数，默认3
*/
private int retry = 3;
}server:
port: 8080
servlet:
context-path: /demo
zk:
url: 127.0.0.1:2181
timeout: 1000
retry: 3/**
* <p>
* Zookeeper配置类
* </p>
*
* @author yangkai.shen
* @date Created in 2018-12-27 14:45
*/
@Configuration
@EnableConfigurationProperties(ZkProps.class)
public class ZkConfig {
private final ZkProps zkProps;
@Autowired
public ZkConfig(ZkProps zkProps) {
this.zkProps = zkProps;
}
@Bean
public CuratorFramework curatorFramework() {
RetryPolicy retryPolicy = new ExponentialBackoffRetry(zkProps.getTimeout(), zkProps.getRetry());
CuratorFramework client = CuratorFrameworkFactory.newClient(zkProps.getUrl(), retryPolicy);
client.start();
return client;
}
}分布式锁的关键注解
/**
* <p>
* 基于Zookeeper的分布式锁注解
* 在需要加锁的方法上打上该注解后，AOP会帮助你统一管理这个方法的锁
* </p>
*
* @author yangkai.shen
* @date Created in 2018-12-27 14:11
*/
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface ZooLock {
/**
* 分布式锁的键
*/
String key();
/**
* 锁释放时间，默认五秒
*/
long timeout() default 5 * 1000;
/**
* 时间格式，默认：毫秒
*/
TimeUnit timeUnit() default TimeUnit.MILLISECONDS;
}分布式锁动态key的关键注解
/**
* <p>
* 分布式锁动态key注解，配置之后key的值会动态获取参数内容
* </p>
*
* @author yangkai.shen
* @date Created in 2018-12-27 14:17
*/
@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface LockKeyParam {
/**
* 如果动态key在user对象中，那么就需要设置fields的值为user对象中的属性名可以为多个，基本类型则不需要设置该值
* <p>例1：public void count(@LockKeyParam({"id"}) User user)
* <p>例2：public void count(@LockKeyParam({"id","userName"}) User user)
* <p>例3：public void count(@LockKeyParam String userId)
*/
String[] fields() default {};
}分布式锁的关键部分
/**
* <p>
* 使用 aop 切面记录请求日志信息
* </p>
*
* @author yangkai.shen
* @date Created in 2018-10-01 22:05
*/
@Aspect
@Component
@Slf4j
public class ZooLockAspect {
private final CuratorFramework zkClient;
private static final String KEY_PREFIX = "DISTRIBUTED_LOCK_";
private static final String KEY_SEPARATOR = "/";
@Autowired
public ZooLockAspect(CuratorFramework zkClient) {
this.zkClient = zkClient;
}
/**
* 切入点
*/
@Pointcut("@annotation(com.xkcoding.zookeeper.annotation.ZooLock)")
public void doLock() {
}
/**
* 环绕操作
*
* @param point 切入点
* @return 原方法返回值
* @throws Throwable 异常信息
*/
@Around("doLock()")
public Object around(ProceedingJoinPoint point) throws Throwable {
MethodSignature signature = (MethodSignature) point.getSignature();
Method method = signature.getMethod();
Object[] args = point.getArgs();
ZooLock zooLock = method.getAnnotation(ZooLock.class);
if (StrUtil.isBlank(zooLock.key())) {
throw new RuntimeException("分布式锁键不能为空");
}
String lockKey = buildLockKey(zooLock, method, args);
InterProcessMutex lock = new InterProcessMutex(zkClient, lockKey);
try {
// 假设上锁成功，以后拿到的都是 false
if (lock.acquire(zooLock.timeout(), zooLock.timeUnit())) {
return point.proceed();
} else {
throw new RuntimeException("请勿重复提交");
}
} finally {
lock.release();
}
}
/**
* 构造分布式锁的键
*
* @param lock 注解
* @param method 注解标记的方法
* @param args 方法上的参数
* @return
* @throws NoSuchFieldException
* @throws IllegalAccessException
*/
private String buildLockKey(ZooLock lock, Method method, Object[] args) throws NoSuchFieldException, IllegalAccessException {
StringBuilder key = new StringBuilder(KEY_SEPARATOR + KEY_PREFIX + lock.key());
// 迭代全部参数的注解，根据使用LockKeyParam的注解的参数所在的下标，来获取args中对应下标的参数值拼接到前半部分key上
Annotation[][] parameterAnnotations = method.getParameterAnnotations();
for (int i = 0; i < parameterAnnotations.length; i++) {
// 循环该参数全部注解
for (Annotation annotation : parameterAnnotations[i]) {
// 注解不是 @LockKeyParam
if (!annotation.annotationType().isInstance(LockKeyParam.class)) {
continue;
}
// 获取所有fields
String[] fields = ((LockKeyParam) annotation).fields();
if (ArrayUtil.isEmpty(fields)) {
// 普通数据类型直接拼接
if (ObjectUtil.isNull(args[i])) {
throw new RuntimeException("动态参数不能为null");
}
key.append(KEY_SEPARATOR).append(args[i]);
} else {
// @LockKeyParam的fields值不为null，所以当前参数应该是对象类型
for (String field : fields) {
Class<?> clazz = args[i].getClass();
Field declaredField = clazz.getDeclaredField(field);
declaredField.setAccessible(true);
Object value = declaredField.get(clazz);
key.append(KEY_SEPARATOR).append(value);
}
}
}
}
return key.toString();
}
}测试分布式锁
@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class SpringBootDemoZookeeperApplicationTests {
public Integer getCount() {
return count;
}
private Integer count = 10000;
private ExecutorService executorService = Executors.newFixedThreadPool(1000);
@Autowired
private CuratorFramework zkClient;
/**
* 不使用分布式锁，程序结束查看count的值是否为0
*/
@Test
public void test() throws InterruptedException {
IntStream.range(0, 10000).forEach(i -> executorService.execute(this::doBuy));
TimeUnit.MINUTES.sleep(1);
log.error("count值为{}", count);
}
/**
* 测试AOP分布式锁
*/
@Test
public void testAopLock() throws InterruptedException {
// 测试类中使用AOP需要手动代理
SpringBootDemoZookeeperApplicationTests target = new SpringBootDemoZookeeperApplicationTests();
AspectJProxyFactory factory = new AspectJProxyFactory(target);
ZooLockAspect aspect = new ZooLockAspect(zkClient);
factory.addAspect(aspect);
SpringBootDemoZookeeperApplicationTests proxy = factory.getProxy();
IntStream.range(0, 10000).forEach(i -> executorService.execute(() -> proxy.aopBuy(i)));
TimeUnit.MINUTES.sleep(1);
log.error("count值为{}", proxy.getCount());
}
/**
* 测试手动加锁
*/
@Test
public void testManualLock() throws InterruptedException {
IntStream.range(0, 10000).forEach(i -> executorService.execute(this::manualBuy));
TimeUnit.MINUTES.sleep(1);
log.error("count值为{}", count);
}
@ZooLock(key = "buy", timeout = 1, timeUnit = TimeUnit.MINUTES)
public void aopBuy(int userId) {
log.info("{} 正在出库。。。", userId);
doBuy();
log.info("{} 扣库存成功。。。", userId);
}
public void manualBuy() {
String lockPath = "/buy";
log.info("try to buy sth.");
try {
InterProcessMutex lock = new InterProcessMutex(zkClient, lockPath);
try {
if (lock.acquire(1, TimeUnit.MINUTES)) {
doBuy();
log.info("buy successfully!");
}
} finally {
lock.release();
}
} catch (Exception e) {
log.error("zk error");
}
}
public void doBuy() {
count--;
log.info("count值为{}", count);
}
}- 如何在测试类中使用 AOP
- zookeeper 实现分布式锁：《Spring Boot 2精髓 从构建小系统到架构分布式大系统》李家智 - 第16章 - Spring Boot 和 Zoo Keeper - 16.3 实现分布式锁