import java.util.concurrent.Callable;
/**
-
@description: create a computing task class, implement the Callable interface, and rewrite the call method
-
@author: xz
-
@create: 2021-06-02 22:06
*/
public class ComputeTask implements Callable {
private String taskName;//Task name
//Task constructor
public ComputeTask(String taskName) {
this.taskName = taskName;
System.out.println("Start creating the calculation task. The calculation task name is:" + taskName);
}
//Method of calculating task
@Override
public Integer call() throws Exception {
Integer result = 0;
for (int i = 1; i <=50; i++) {
result = +i;
}
System.out.println("[Calculation task]"+taskName +"Execution completed.");
return result;
}
}
**2,Create a test class**
package com.xz.thread.FutureTask;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;
/**
-
@description:
-
@author: xz
-
@create: 2021-06-01 22:44
*/
public class Demo {
public static void main(String[] args) {
//Task collection
List<FutureTask<Integer>> futureTasks = new ArrayList<>();
//Create a fixed length thread pool
ExecutorService pool = Executors.newFixedThreadPool(5);
for (int i = 1; i <= 10; i++) {
//Instantiate FutureTask and pass in the calculation task class
FutureTask<Integer> futureTask = new FutureTask<>(new ComputeTask(i + ""));
//Add to task collection
futureTasks.add(futureTask);
//Submit task to thread pool
pool.submit(futureTask);
}
System.out.println("After all [calculation tasks] are submitted, the main thread starts to execute");
System.out.println("[Main thread task] start============");
//The main thread sleeps for 5 seconds and simulates the main thread to do some tasks
try {
Thread.sleep(5000);
System.out.println("[Main thread task] start executing some tasks============");
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("[End of main thread task============");
//Used to print job execution results
Integer result = 0;
for (FutureTask<Integer> task : futureTasks) {
try {
//The get() method of FutureTask will automatically block until the task execution result is obtained
result += task.get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
//Close thread pool
pool.shutdown();
System.out.println("Multithreading multitasking execution results:" + result);
}
}
**3,The output results are as follows:**
Start creating [calculation task]. Calculation task name: 1
Start to create [calculation task]. Calculation task name: 2
Start creating [calculation task]. Calculation task name: 3
Start to create [calculation task]. Calculation task name: 4
Start creating [calculation task]. Calculation task name: 5
Start creating [calculation task]. Calculation task name: 6
Start creating [calculation task]. Calculation task name: 7
Start creating [calculation task]. Calculation task name: 8
Start creating [calculation task]. Calculation task name: 9
Start creating [calculation task]. Calculation task name: 10
After all [calculation tasks] are submitted, the main thread starts to execute
[main thread task] start============
[calculation task] 1 execution completed.
[calculation task] 2 execution is completed.
[calculation task] 6 execution is completed.
[calculation task] 7 execution is completed.
[calculation task] 9 execution is completed.
[calculation task] 10 execution completed.
[calculation task] 8 execution completed.
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]9 execution completed.
[calculation task] 10 execution completed.
[calculation task] 8 execution completed.
last
That's all I want to share with you this time
The information is all in -*** My study notes: big factory interview real questions + microservices + MySQL+Java+Redis + algorithm + Network + Linux+Spring family bucket + JVM + study note map***
Finally, share a big gift package (learning notes) of the ultimate hand tearing architecture: distributed + microservices + open source framework + performance optimization
