Java Multithreaded series seven--executorservice

The Java.util.concurrent.ExecutorService interface provides a number of methods for threading management

Method	Description
Shutdown	Refuses to receive new tasks, closes when the submitted task is executed, and does not block the host thread, if blocking is required to implement with Awaittermination
Shutdownnow	Stops all tasks that are in progress, suspends tasks that are not executed, and shuts down, and the host thread does not block, and can be implemented with awaittermination if blocking is required
Awaittermination	When shutdown occurs, blocks the host thread until the agreed time is over or all tasks are completed
Submit	Submit task Callable/runnable, can use the Get () method of the future to block the host thread until the end of the task to return results

With these methods, you can implement various functions of the thread pool based on this interface (for example, java.util.concurrent.threadpoolexecutor/ Java.util.concurrent.ScheduledThreadPoolExecutor), take Java.util.concurrent.ThreadPoolExecutor as an example, with a detailed explanation of its parameters

When a new task throws an exception to the upper limit

Name	Type	description
Corepo olsize	int	thread pool minimum number of threads
maximumpoolsize	int	thread pool most Large number of threads
keepalivetime	long	thread idle time, if the number of threads is greater than corepoolsize, threads with idle time exceeding this value will be stopped for recycling
Unit	timeunit	keepalivetime time Unit
workqueue	Blockingqueue<runnable>	committed but not executed task queue
threadfactory	Threa Dfactory	Create a new thread factory
handler	rejectedexecutionhandler	when the thread pool or queue reaches Handling class

At the same time, the Java.util.concurrent.Executors class provides tool methods based on the Java.util.concurrent.ThreadPoolExecutor class, and the common methods are

Method	Description
Newfixedthreadpool	Thread pool with a fixed number of threads
Newsinglethreadexecutor	The thread pool contains only one worker thread
Newcachedthreadpool	Create threads on Demand, if no threads are available in the thread pool, create a new thread and join until the number of threads reaches the upper limit (integer.max_value)

The test code is as follows

Importjava.util.Date;Importjava.util.concurrent.Callable;Importjava.util.concurrent.ExecutionException;ImportJava.util.concurrent.ExecutorService;Importjava.util.concurrent.Executors;Importjava.util.concurrent.Future;ImportJava.util.concurrent.TimeUnit;ImportOrg.junit.Assert;Importorg.junit.Test;/*** @Description: Test Executorservice*/ Public classThreadexecutorservicetest {Private Static FinalString this_is_shutdown_with_await_termination = "This is Shutdownwithawaittermination"; Private Static Final intRESULT = 111; Private Static BooleanSubmitrunnable ()throwsinterruptedexception, executionexception {executorservice executorservice=Executors.newsinglethreadexecutor (); Future<?> future = Executorservice.submit (NewRunnable () {@Override Public voidrun () {System.out.println ("This is submitrunnable");        }        }); returnFuture.get () = =NULL; }    Private StaticInteger Submitrunnablewithresult ()throwsinterruptedexception, executionexception {executorservice executorservice=Executors.newsinglethreadexecutor (); Future<Integer> future = Executorservice.submit (NewRunnable () {@Override Public voidrun () {System.out.println ("This is Submitrunnablewithresult");        }}, RESULT); returnFuture.get (); }    Private StaticInteger submitblockcallable ()throwsinterruptedexception, executionexception {executorservice executorservice= Executors.newfixedthreadpool (1); Future<Integer> future = Executorservice.submit (NewCallable<integer>() {@Override PublicInteger Call ()throwsException {System.out.println ("This is submitblockcallable"); returnRESULT;        }        }); returnFuture.get ();//Blocking    }    Private Static BooleanSubmitnonblockcallable ()throwsinterruptedexception, executionexception {executorservice executorservice= Executors.newfixedthreadpool (1); Future<Integer> future = Executorservice.submit (NewCallable<integer>() {@Override PublicInteger Call ()throwsException {System.out.println ("This is submitnonblockcallable"); returnRESULT;        }        });  while(!future.isdone ()) {//non-blockingSystem.out.println (NewDate ()); }        returnFuture.isdone (); }    Private StaticString shutdown ()throwsinterruptedexception, executionexception {executorservice executorservice= Executors.newfixedthreadpool (1); FinalStringBuilder SB =NewStringBuilder (); Executorservice.submit (NewCallable<integer>() {@Override PublicInteger Call ()throwsException {thread.sleep (10000); Sb.append ("This is shutdown"); returnRESULT;        }        });        Executorservice.shutdown (); returnsb.tostring (); }    Private StaticString shutdownwithawaittermination ()throwsinterruptedexception, executionexception {executorservice executorservice= Executors.newfixedthreadpool (1); FinalStringBuilder SB =NewStringBuilder (); Executorservice.submit (NewCallable<integer>() {@Override PublicInteger Call ()throwsException {thread.sleep (10000);                Sb.append (this_is_shutdown_with_await_termination); returnRESULT;        }        });        Executorservice.shutdown ();        Executorservice.awaittermination (Integer.max_value, timeunit.days); returnsb.tostring (); } @Test Public voidTest ()throwsinterruptedexception, executionexception {assert.asserttrue (submitrunnable ());        Assert.assertequals (RESULT, Submitrunnablewithresult (). Intvalue ());        Assert.assertequals (RESULT, Submitblockcallable (). Intvalue ());        Assert.asserttrue (Submitnonblockcallable ());        Assert.asserttrue (Shutdown (). IsEmpty ());    Assert.assertequals (This_is_shutdown_with_await_termination, Shutdownwithawaittermination ()); }}

Java Multithreaded series seven--executorservice