Java中的Future & Callable

最简单的基本流程是：

1. Callable任务通过ExecutorService来提交；
2. 任务结束后返回的结果交给Future；
3. Future通过get()方法去获得实际的运算结果。

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

class Merge implements Callable<String>{
    
    private String strA;
    private String strB;
    
    Merge(String strA, String strB){
        this.strA = strA;
        this.strB = strB;
    }

    @Override
    public String call() throws Exception {
        return strA+strB;
    }
    
}

public class CallableTest {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        ExecutorService es = Executors.newFixedThreadPool(1);
        Merge task = new Merge("Hello " ,"World!");
        Future<String> future = es.submit(task);
        String result = future.get();
        System.out.println(result);

        es.shutdown();
    }
}