需求背景
Springboot集成分佈式鎖實現：基於Redis實現。通過使用Spring Integration它提供的全局鎖實現，同時，它還提供了其他存儲的分佈式鎖實現：如Gemfire，JDBC，Zookeeper等。
代碼演示
1. 項目目錄結構：
2. pom.xml依賴組件
<?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>
<!-- 構建成可運行的Web項目 -->
<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>
<!-- 分佈式鎖實現 -->
<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：這裏我把默認redis的端口6379，改成了7379，同時增加了redis密碼驗證（教程），建議你也都這麼做
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";
}
}
訪問接口：http://localhost:9090/test
2019-08-28 23:02:51,189 [http-nio-9090-exec-3] [com.md.demo.MyHttpInterceptor] [INFO] (MyHttpInterceptor.java:38)- 請求參數, 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
啓動第二個實例，比如9091端口，並迅速訪問兩個實例的/test接口：http://localhost:9091/test，會在第二個實例上看到日誌：
2019-08-28 23:04:46,878 [http-nio-9091-exec-3] [com.md.demo.MyHttpInterceptor] [INFO] (MyHttpInterceptor.java:38)- 請求參數, 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)
說明第二個實例沒有拿到鎖了，即證明了分佈式鎖的存在
實現原理
可見源碼：RedisLockRegistry.java文件
完整源碼下載
參考資料
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SpringBoot從入門到精通教程（二十一）- MongoDB集成用法
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