CODEWITHSUNDEEP
javaspringmultithreadingspring-mvc
Parys
Parys

Reputation: 49

Spring threads in web app

I am writing server for MMO browser game, and I need to make few threads. They will be running all the time with some sleep time. Is it good idea, to use spring threads like this?

@Component
@Scope("prototype")
public class PrintTask2 implements Runnable{

String name;

public void setName(String name){
    this.name = name;
}

@Override
public void run() {

    System.out.println(name + " is running");

    try {
        Thread.sleep(5000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    System.out.println(name + " is running");

}

}

with task executor implemented as bean?

<bean id="taskExecutor"
       class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
    <property name="corePoolSize" value="5" />
    <property name="maxPoolSize" value="10" />
    <property name="WaitForTasksToCompleteOnShutdown" value="true" />
</bean>

Also, threads are started in singleton also defined as a bean.

What can be wrong in my approach?

Upvotes: 3

Views: 1681

Answers (2)

kkflf
kkflf

Reputation: 2570

You can use @Scheduled(fixedDelay = 5000) to execute a method periodic. Remember to set @EnableScheduling for class containing your main method.

There are two options for the @Scheduled annotation - fixedDelayand fixedRate.

fixedDelay will continuously execute your method with a delay of X miliseconds after the last execution has finished.

fixedRate will continuously execute your method with at a fixed date. So every X milisecond this method will be executed regardless if the last execution has finished.

You can also use @Async if you want to process a bunch of objects all at once. Once again, you need to add @EnableAsync to your class with your main method.

Example

//Remember to set @EnableScheduling
//in the class containing your main method
@SpringBootApplication
@EnableScheduling
@EnableAsync
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class);
    }
}

@Component
public class ScheduledTasks {

List<YourObject> myObjects;

    //This method will run every 5 second.
    @Scheduled(fixedDelay = 5000)
    public void yourMethodName() {
        //This will process all of your objects all at once using treads
        for(YourObject yo : myObjects){
            yo.process();
        }
    }
}

public class YourObject {

    Integer someTest = 0;

    @Async
    public void process() {
       someTest++;
    }
}

Bonus You can get rid of your XML configuration for the pool size by extending AsyncConfigurerSupport and override getAsyncExecutor. More information about this approach can be found at the below links

I suggest that you take a look at:

https://spring.io/guides/gs/scheduling-tasks/

https://spring.io/guides/gs/async-method/

Upvotes: 2

Sampisa
Sampisa

Reputation: 1583

You can use @Async in case you want to invoke a single thread programmatically (e.g. you want to send 50 mail and you send them creating 50 different thread, each one to send a single message, then wait until all threads end), or @Scheduled to let a method / thread run at fixed rate (or after some time from previous execution end).

You can put an eye on https://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html#scheduling-annotation-support for further details.

@Service
public class MyAsyncStuff {
    @Async
    public Future<String> callMe(String param) {  
       // do your work here...         
       return new AsyncResult<String>("Sent: "+param);           
    }
}

@Service 
public class MyWorker {
    @Inject
    MyAsyncStuff stuff;

    public void invoker() {
        List<Future<String>> futures = new Arraylist<>();
        for (int i=0; i<10; i++) {
           futures.add(stuff.callMe("Invoked "+i));
        }
        for (Future<String> fut : futures) {
           try {
              System.out.println(futures.get();
           } catch (Exception e) {
             // Spock? Do something!
           }
        }
     }
 }

Upvotes: 0

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