代码语言：javascript复制
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.*;
/**
* @author
* @date 2019/12/13
* @desc 基于线程安全的缓存工具类
*/
public class CacheUtil {
private static Logger LOGGER = LoggerFactory.getLogger(CacheUtil.class);
private static final ConcurrentMap<String, Future<String>> cache = new ConcurrentHashMap<>();
public static String getByKey(String key) {
Future<String> future = cache.get(key);
if (future == null) {
return null;
}
try {
return future.get();
} catch (Exception e) {
LOGGER.error("get wk_id from cache error:{}", e);
}
return null;
}
/**
* 存入缓存
*
* @param key
* @param val
* @return
*/
public static String putIntoCache(String key, String val) {
Future<String> future = cache.get(key);
if (future == null) {
Callable<String> callable = new Callable<String>() {
@Override
public String call() throws Exception {
return new String(val);
}
};
FutureTask<String> task = new FutureTask<>(callable);
future = cache.putIfAbsent(key, task);
if (future == null) {
future = task;
task.run();
}
}
try {
return future.get();
} catch (Exception e) {
cache.remove(key);
LOGGER.error("put wk_id into cache error:{}", e);
}
return null;
}
/**
* 更新缓存中相应的值
*
* @param key
* @param val
* @return
*/
public static String updateCache(String key, String val) {
Future<String> future = cache.get(key);
if (future == null) {
return null;
}
Callable<String> callable = new Callable<String>() {
@Override
public String call() throws Exception {
return new String(val);
}
};
FutureTask<String> task = new FutureTask<>(callable);
Future<String> replace = cache.replace(key, task);
if (replace != null) {
future = task;
task.run();
}
try {
return task.get();
} catch (Exception e) {
cache.remove(key);
LOGGER.error("update cache error:{}", e);
}
return null;
}
}
