guava做本地緩存

package tool;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import java.util.Optional;
import java.util.Random;
import java.util.concurrent.TimeUnit;

public class GuavaTest {

    private static Integer generateNewMsgCode(String phone) {
        Integer msgCode = (new Random()).nextInt(1000000 - 100000) + 100000;
        System.out.println("generate new Msg code. phone=" + phone + ",msgCode=" + msgCode);
        return msgCode;
    }

    private static LoadingCache<String, Optional<Integer>> msgCodeCache =
        CacheBuilder.newBuilder()
            .maximumSize(1000L)
            .expireAfterWrite(5, TimeUnit.SECONDS)//5s過期
            .concurrencyLevel(10)
            .build(new CacheLoader<String, Optional<Integer>>() {
                @Override
                public Optional<Integer> load(String phone) throws Exception {
                    return Optional.ofNullable(generateNewMsgCode(phone));
                }
            });

    private static Integer getMsgCodeByPhone(String phone){
        return msgCodeCache.getUnchecked(phone).orElse(0);
    }

    public static void main(String[] args) throws InterruptedException {

        String phone = "13100000000";

        //first
        System.out.println("first .msgCode:" + getMsgCodeByPhone(phone));

        Thread.sleep(1000);
        //second
        System.out.println("second .msgCode:" + getMsgCodeByPhone(phone));

        Thread.sleep(5000);
        //third
        System.out.println("third .msgCode:" + getMsgCodeByPhone(phone));

    }
}

           

"com.google.guava:guava:$guavaVersion"
           

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