springboot 整合GuavaCache緩存

Guava Cache是一種本地緩存機制，之所以叫本地緩存，是因為它不會把緩存數據放到外部文件或者其他服務器上，而是存放到了應用內存中。

Guava Cache的優點是：簡單、強大、輕量級。

 

GuavaCache適用場景：

1.某些接口或者鍵值會被查詢多次以上；

2.願意使用或犧牲一些內存空間來提升訪問或者計算速度；

3.緩存內容或者結果值較小，不會超過內存總容量；

 

GuavaCache中基於注解的聲明式緩存操作     

@Cacheable 觸發緩存邏輯

Spring 在執行 @Cacheable 標注的方法前先查看緩存中是否有數據，如果有數據，則直接返回緩存數據；若沒有數據，執行該方法並將方法返回值放進緩存。

參數： value緩存名、 key緩存鍵值、 condition滿足緩存條件、unless否決緩存條件

@CacheEvict

觸發緩存逐出邏輯

方法執行成功后會從緩存中移除相應數據。

參數： value緩存名、 key緩存鍵值、 condition滿足緩存條件、 unless否決緩存條件、 allEntries是否移除所有數據 （設置為true時會移除所有緩存）

@CachePut

和 @Cacheable 類似，但會把方法的返回值放入緩存中, 主要用於數據新增和修改方法。

pom.xml配置文件：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
    <version>1.5.9.RELEASE</version>
</dependency>

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>19.0</version>
</dependency>

 

GuavaCacheConfig：

/**
 * Copyright (c) 2020, All Rights Reserved.
 *
*/

package com.demo.server.config;

import java.util.concurrent.TimeUnit;

import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.guava.GuavaCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.google.common.cache.CacheBuilder;


@Configuration
@EnableCaching
public class GuavaCacheConfig {
    
    @Bean
    public CacheManager cacheManager() { 
        GuavaCacheManager cacheManager = new GuavaCacheManager();
        cacheManager.setCacheBuilder(
            CacheBuilder.newBuilder().
            expireAfterWrite(10, TimeUnit.SECONDS). //存活時間10秒
            maximumSize(1000));     //最大線程數
        return cacheManager;
    }

}

CacheController：

/**
 * Copyright (c) 2020, All Rights Reserved.
 *
*/

package com.demo.server.guava;


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

@RestController
@RequestMapping(value = "/guava")
public class CacheController {
    
    @Autowired
    private CacheService cacheService;

    /**
     * 查詢方法
     */
    @RequestMapping(value = "/get", method = RequestMethod.GET)
    public String getByCache() {
        Long startTime = System.currentTimeMillis();
        long timestamp = this.cacheService.getByCache();
        Long endTime = System.currentTimeMillis();
        System.out.println("耗時: " + (endTime - startTime));
        return timestamp+"";
    }

    /**
     * 保存方法
     */
    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public void save() {
        this.cacheService.save();
    }

    /**
     * 刪除方法
     */
    @RequestMapping(value = "delete", method = RequestMethod.DELETE)
    public void delete() {
        this.cacheService.delete();
    }
}

CacheService：

/**
 * Copyright (c) 2020, All Rights Reserved.
 *
*/

package com.demo.server.guava;

import java.sql.Timestamp;

import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;


@Service
public class CacheService {

    @CachePut(value = "guavacache")
    public long save() {
        long timestamp = new Timestamp(System.currentTimeMillis()).getTime();
        System.out.println("進行緩存：" + timestamp);
        return timestamp;
    }
 
    @CacheEvict(value = "guavacache")
    public void delete() {
        System.out.println("刪除緩存");
    }
 
    @Cacheable(value = "guavacache")
    public long getByCache() {
        try {
            Thread.sleep(3 * 1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return new Timestamp(System.currentTimeMillis()).getTime();
    }

}

Application：

package com.demo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.Banner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {
    private static final Logger LOG = LoggerFactory.getLogger(Application.class);

    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(Application.class);
        app.setBannerMode(Banner.Mode.OFF);
        app.setWebEnvironment(true);
        app.run(args);
        LOG.info("**************** Startup Success ****************");
    }
}