模拟一个本地缓存，统计缓存的命中率

为了测试线上服务，加缓存的效果，模拟了一个本地缓存，去测试一下加缓存后的命中率，代码如下：

 

 

import java.util.Date;
import java.util.Random;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 统计任务，统计一下缓存的命中率
 */
public class StatTask {

    public static Log logger = LogFactory.getLog("stat-cache");

    public static AtomicInteger total = new AtomicInteger(0);

    public static AtomicInteger cachedNum = new AtomicInteger(0);

    public static ConcurrentHashMap<String, AtomicInteger> buffer = new ConcurrentHashMap<String, AtomicInteger>();

    public static Executor executor = Executors.newFixedThreadPool(Runtime.getRuntime()
            .availableProcessors() * 2);

    public static void submit(final String url) {
        executor.execute(new Runnable() {

            @Override
            public void run() {
                try {
                    logger.info("link:" + url);
                    if (buffer.containsKey(url)) {
                        int num = buffer.get(url).incrementAndGet();
                        if (num % 10 == 0) {
                            logger.warn(String.format("url:%s be cached %d", url, num));
                        }
                        cachedNum.incrementAndGet();
                    } else {
                        buffer.put(url, new AtomicInteger());
                    }
                    total.incrementAndGet();
                    int cachedNumber = cachedNum.get();
                    int totalNum = total.get();
                    if (cachedNumber > 0 && cachedNumber % 100 == 0) {
                        logger.warn(String.format(
                                "cache hit %d and total:%d, 1.percentage of hits:%s", cachedNumber,
                                totalNum, cachedNumber / (1.0 * totalNum)));
                    }
                } catch (Exception e) {
                    logger.error("统计cache命中率计数器出错:" + e.getMessage());
                }
            }
        });
    }


}