SpringBoot从入门到精通教程（二十）- 分布式锁用法（基于Redis实现）

需求背景

Springboot集成分布式锁实现：基于Redis实现。通过使用Spring Integration它提供的全局锁实现，同时，它还提供了其他存储的分布式锁实现：如Gemfire，JDBC，Zookeeper等。

代码演示

1. 项目目录结构：

2. pom.xml依赖组件

<?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>

	<parent>
		<groupId>com.md</groupId>
		<artifactId>spring-boot2-parent</artifactId>
		<version>0.0.1-SNAPSHOT</version>
		<relativePath>../pom.xml</relativePath>
	</parent>

	<artifactId>spring-boot2-distributed-lock</artifactId>
	<packaging>jar</packaging>

	<name>spring-boot2-distributed-lock</name>
	<description>Spring Boot, MVC, Rest API for App</description>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
		<!-- 构建成可运行的Web项目 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>net.sf.json-lib</groupId>
			<artifactId>json-lib-ext-spring</artifactId>
		</dependency>
		<!-- 分布式锁实现 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-integration</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.integration</groupId>
			<artifactId>spring-integration-redis</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

3. application.yml配置文件

server:
   port: 9090
spring:
   redis:
      host: localhost
      port: 7379
      password: a123456
      timeout: 10000
      max-wait: -1

注：这里我把默认redis的端口6379，改成了7379，同时增加了redis密码验证（教程），建议你也都这么做

4. RedisLockConfiguration.java配置

package com.md.demo;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.integration.redis.util.RedisLockRegistry;

@Configuration
public class RedisLockConfiguration {
	
	@Bean
	public RedisLockRegistry redisLockRegistry(RedisConnectionFactory redisConnectionFactory) {
		return new RedisLockRegistry(redisConnectionFactory, "spring-boot");
	}
	
}

案例演示

InitRest.java文件

package com.md.demo.rest;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.integration.redis.util.RedisLockRegistry;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author Minbo
 */
@RestController
public class InitRest {

	protected static Logger logger = LoggerFactory.getLogger(InitRest.class);

	@Autowired
	private RedisLockRegistry redisLockRegistry;

	/**
	 * http://localhost:9090/hello
	 * 
	 * @return
	 */
	@GetMapping("/hello")
	public String hello() {
		logger.info("hello");
		return "Hello greetings from spring-boot2-distributed-lock";
	}

	/**
	 * http://localhost:9090/test
	 * 
	 * @return
	 */
	@GetMapping("test")
	public String test() throws InterruptedException {
		Lock lock = this.redisLockRegistry.obtain("lock");
		boolean b1 = lock.tryLock(3, TimeUnit.SECONDS);
		logger.info("b1 is : {}", b1);

		TimeUnit.SECONDS.sleep(5);

		boolean b2 = lock.tryLock(3, TimeUnit.SECONDS);
		logger.info("b2 is : {}", b2);

		lock.unlock();
		lock.unlock();
		
		return "success";
	}
}

访问接口：http://localhost:9090/test

2019-08-28 23:02:51,189 [http-nio-9090-exec-3] [com.md.demo.MyHttpInterceptor] [INFO] (MyHttpInterceptor.java:38)- 请求参数, url: http://localhost:9090/test, method: GET, params: null
2019-08-28 23:02:51,238 [http-nio-9090-exec-3] [com.md.demo.rest.InitRest] [INFO] (InitRest.java:44)- b1 is : true
2019-08-28 23:02:56,285 [http-nio-9090-exec-3] [com.md.demo.rest.InitRest] [INFO] (InitRest.java:49)- b2 is : true

启动第二个实例，比如9091端口，并迅速访问两个实例的/test接口：http://localhost:9091/test，会在第二个实例上看到日志：

2019-08-28 23:04:46,878 [http-nio-9091-exec-3] [com.md.demo.MyHttpInterceptor] [INFO] (MyHttpInterceptor.java:38)- 请求参数, url: http://localhost:9091/test, method: GET, params: null
2019-08-28 23:04:50,016 [http-nio-9091-exec-3] [com.md.demo.rest.InitRest] [INFO] (InitRest.java:44)- b1 is : false
2019-08-28 23:04:55,066 [http-nio-9091-exec-3] [com.md.demo.rest.InitRest] [INFO] (InitRest.java:49)- b2 is : true
2019-08-28 23:04:55,113 [http-nio-9091-exec-3] [org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/].[dispatcherServlet]] [ERROR] (DirectJDKLog.java:182)- Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: You do not own lock at spring-boot:lock] with root cause
java.lang.IllegalStateException: You do not own lock at spring-boot:lock
	at org.springframework.integration.redis.util.RedisLockRegistry$RedisLock.unlock(RedisLockRegistry.java:297)
	at com.md.demo.rest.InitRest.test(InitRest.java:52)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)

说明第二个实例没有拿到锁了，即证明了分布式锁的存在

实现原理

可见源码：RedisLockRegistry.java文件

完整源码下载

我的Github源码地址：

https://github.com/hemin1003/spring-boot-study/tree/master/spring-boot2-study/spring-boot2-parent/spring-boot2-distributed-lock

该系列教程

SpringBoot系列

参考资料

Spring-integration官方仓库

Springboot集成分布式缓存Redis

【总结】SpringBoot2实现分布式锁

至此，全部介绍就结束了

------------------------------------------------------

------------------------------------------------------

关于我（个人域名）

我的开源项目集Github

期望和大家一起学习，一起成长，共勉，O(∩_∩)O谢谢

欢迎交流问题，可加个人QQ 469580884，

或者，加我的群号 751925591，一起探讨交流问题

不讲虚的，只做实干家

Talk is cheap，show me the code