Guava 工具类之Cache的使用

package com.study;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import org.junit.Test;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import com.google.common.cache.Cache;;
/**
 * guava cache 测试
 *     
 * @author    pengbo.zhao
 * @data 2019年11月5日 上午10:24:15
 *     
 * 
 *  cache的创建
 * 
 *  {@link #createCache()}    创建一个简单的cache
 *  
 *  
 *  
 */
public class GuavaCache {
    
    
    
    @Test
    public void createCache() throws ExecutionException{
        Cache<String,String> cache = CacheBuilder.newBuilder()
                                    
                                    //设置并发数(以获取当前操作系统cpu数来确定并发数)
                                    .concurrencyLevel(Runtime.getRuntime().availableProcessors())
                                    //设置初始容量
                                    .initialCapacity(1000)
                                    //设置最大存储量
                                    .maximumSize(900)
                                    //设置过期时间(3秒内没有使用)
                                    .expireAfterAccess(3,TimeUnit.SECONDS)
                                    //设置过期时间(写入3秒内过期)
                                    .expireAfterWrite(3, TimeUnit.SECONDS)
                                    //设置引用清除(设置弱引用存储值)
                                    .weakValues()
                                    //设置统计信息    
                                    .recordStats()
                                    //设置移除通知
                                    .removalListener(new RemovalListener<String, String>() {
                                        @Override
                                        public void onRemoval(RemovalNotification<String, String> notification) {
                                            System.out.println(notification.getKey()+"-"+notification.getValue()+" is remove");
                                        }
                                    })
                                    //构建
                                    .build();
        
            cache.put("key1", "value1");
            System.out.println(cache.getIfPresent("key1"));
            String key2 = cache.get("key2",new Callable<String>() {
                @Override
                public String call() throws Exception {
                    return "value2";
                }
            });
            System.out.println(key2);
    }
}