Guava线程池踩坑记录

Guava

google的并行化框架，研究不深，在此不班门弄斧，送上一个链接

坑描述

其实说坑有点儿委屈google了，因为根本不是guava的问题，是我自己的问题。长话短说，线程池记得关闭，记得关闭，记得关闭啊喂！！！重要的事情说三遍！！！

• 后果 ： 线程池没关你知道有多严重么？你肯定想不到，我把我们api的dev和beta server统统搞挂了啊，是server挂了，不是service挂了啊，哭！！！

• 细节：上代码

//max thread num : 20final ExecutorService pool = Executors.newFixedThreadPool(20);ListeningExecutorService service = MoreExecutors.listeningDecorator(pool);//        ListeningExecutorService executor = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(20));List<Callable<Map<String, Object>>> tasks;List<ListenableFuture<Map<String, Object>>> futures = Lists.newArrayList();for(Map<String, Object> inputApp : appList) {    ListenableFuture queryApp = service.submit(new Callable() {        public Map<String, Object> call() {            Map<String, Object>skyaidQueryRet = queryApp(inputApp, fromRedis);            return  skyaidQueryRet;        }    });    futures.add(queryApp);}final ListenableFuture<List<Map<String, Object>>> resultsFuture = Futures.successfulAsList(futures);try {    // block until all tasks are done    retList = resultsFuture.get();} catch (Exception e) {    e.printStackTrace();    pool.shutdown();}pool.shutdown();//重点就是这行

• 错误： 我一开始忘记加 pool.shutdown();这一句，直接导致的就是线程池中的task即使都执行完，资源并不会释放，最终回答道jvm的线程创建上限，导致不能创建任何新的线程，从而全线崩溃，甚至影响到了ssh到server都不能执行命令！

• throw error:

java.lang.RuntimeException: java.lang.reflect.InvocationTargetException    at com.jfinal.aop.Invocation.invoke(Invocation.java:85)    at ...//省略部分描述    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)    at java.lang.Thread.run(Thread.java:745)Caused by: java.lang.reflect.InvocationTargetException    at sun.reflect.GeneratedMethodAccessor99.invoke(Unknown Source)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:497)    at com.jfinal.aop.Invocation.invoke(Invocation.java:71)    ... 23 moreCaused by: java.lang.OutOfMemoryError: unable to create new native thread    at java.lang.Thread.start0(Native Method)    at ...//省略部分描述    at com.trendmicro.skyaid.controller.ArsController.v1(ArsController.java:35)    ... 27 more

The end！