springboot-redis-lock-cache 使用redis分布式锁

1.创建springboot项目

2.pom.xml

<?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>

    <groupId>com.nbug</groupId>
    <artifactId>springboot-redis-cache-lock</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot-redis-cache-lock</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </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-cache</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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>
        </dependency>
    </dependencies>

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

    </build>


</project>

3.application.yml

spring:
  redis:
    host: localhost
    port: 6379
  cache:
    type: redis

4.CacheTest

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class CacheTest {
    @Autowired
    public RedisCache redisCache;

    @RequestMapping("/getList")
    public List get(){
        return redisCache.get();
    }

    @RequestMapping("/delete")
    public int delete(){
        return redisCache.delete();
    }


}

5.LockTest

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.atomic.AtomicInteger;

@RestController
@Slf4j
public class LockTest {

    @Autowired
    private RedisLock redisLock;

    private static final int TIMEOUT = 10 * 1000; //超时时间 10s
    //库存
    //private AtomicInteger count = new AtomicInteger(100);
    private int count =100;
    //抢购成功数
    private int success=0;

    @RequestMapping("/testLock")
    public String testLock() {

        long time = System.currentTimeMillis() + TIMEOUT;
        //加锁
        boolean islock = redisLock.lock("key", String.valueOf(time));
        //没有获取到锁
        if (!islock){
            log.info("服务器忙，请重试");
            return "服务器忙，请重试";

        }
        //获取锁之后
        if (count==0){
            redisLock.unlock("key",String.valueOf(time));
            log.info("抢完了,成功数为：{}",success);
            return "抢完了";
        }
        //因为获取到的锁的线程只有一个，所以这里计数也不会出错
        //库存减去1
        count--;
   /*     if (count.get()==0){
            redisLock.unlock("key",String.valueOf(time));
            log.info("抢完了,成功数为：{}",success);
            return "抢完了";
        }
        count.getAndDecrement();*/

        //解锁
        redisLock.unlock("key",String.valueOf(time));
        success++;
        log.info("抢购成功 成功数为：{} 库存剩余为：{}",success,count);
        return "抢购成功";

    }


}

6.RedisCache

import lombok.extern.slf4j.Slf4j;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

@Component
@CacheConfig(cacheNames = "/getList")
@Slf4j
public class RedisCache {
    //该方法开启缓存
    @Cacheable(key = "'list'")
    public List get() {
        String a = "aaaaaaa";
        String b = "aaaaaaabbbbccccccccc";
        String c = "aaaaaaaccc";
        List list = new ArrayList();
        list.add(a);
        list.add(b);
        list.add(c);
        log.info("执行了get方法，没有使用缓存");
        return list;
    }

    //如果数据库数据进行了更新，在这行该方法后，删除指定key的缓存
    @CacheEvict(key = "'list'")
    public int delete() {
        log.info("删除了list缓存");
        return 1;
    }

}

7.RedisLock

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

@Component
@Slf4j
public class RedisLock {

    @Autowired
    private StringRedisTemplate redisTemplate;


    /**
     * 加锁
     * @param key
     * @param value 当前时间+超时时间
     * @return
     */
    public boolean lock(String key, String value) {
        if(redisTemplate.opsForValue().setIfAbsent(key, value)) {
            return true;
        }
        //currentValue=A   这两个线程的value都是B  其中一个线程拿到锁
        String currentValue = redisTemplate.opsForValue().get(key);
        //如果锁过期
        if (!StringUtils.isEmpty(currentValue)
                && Long.parseLong(currentValue) < System.currentTimeMillis()) {
            //获取上一个锁的时间
            String oldValue = redisTemplate.opsForValue().getAndSet(key, value);
            if (!StringUtils.isEmpty(oldValue) && oldValue.equals(currentValue)) {
                return true;
            }
        }

        return false;
    }

    /**
     * 解锁
     * @param key
     * @param value
     */
    public void unlock(String key, String value) {
        try {
            String currentValue = redisTemplate.opsForValue().get(key);
            if (!StringUtils.isEmpty(currentValue) && currentValue.equals(value)) {
                redisTemplate.opsForValue().getOperations().delete(key);
            }
        }catch (Exception e) {
            log.error("【redis分布式锁】解锁异常, {}", e);
        }
    }

}

8.启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication
@EnableCaching
public class SpringbootRedisCacheLockApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootRedisCacheLockApplication.class, args);
    }
}

9.测试 http://localhost:8080/testLock

测试缓存 http://localhost:8080/getList

http://localhost:8080/delete