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package cn.netkiller.test;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class Test {
private final ExecutorService executor = Executors.newSingleThreadExecutor();
public Future<Integer> calculate(Integer input) {
return executor.submit(() -> {
System.out.println("Calculating..." + input);
Thread.sleep(1000);
return input * input;
});
}
public static void main(String[] args) throws InterruptedException, ExecutionException {
Test test = new Test();
Future<Integer> future = test.calculate(12);
Integer value = future.get();
System.out.println(value);
}
}
设置超时时间
value = future.get(500, TimeUnit.MILLISECONDS);
设置超时时间
value = future.get(500, TimeUnit.MILLISECONDS);
取消运行
boolean canceled = future.cancel(true);
判断是否完成
while(!future.isDone()) {
System.out.println("Calculating...");
Thread.sleep(300);
}
ExecutorService executor = Executors.newSingleThreadExecutor();
Future<String> future1 = executor.submit(() -> "AAA");
Future<String> future2 = executor.submit(() -> "BBB");
Future<String> future3 = executor.submit(() -> "CCC");
Stream<String> stream = Stream.of(future1, future2, future3)
.map(func -> {
// System.out.println(Thread.currentThread().getName());
try {
return func.get(5L, TimeUnit.SECONDS);
} catch (InterruptedException e) {
throw new RuntimeException(e);
} catch (ExecutionException e) {
throw new RuntimeException(e);
} catch (TimeoutException e) {
throw new RuntimeException(e);
}
}).filter(Objects::nonNull);
stream.forEach(System.out::println);
public class OldConcurrentService {
privatefinal ExecutorService executor = Executors.newFixedThreadPool(2);
public Map<String, Object> getPageData(String userId) throws Exception {
// 1. 提交两个异步任务
Future<String> userFuture = executor.submit(() -> fetchUserInfo(userId));
Future<String> productFuture = executor.submit(() -> fetchProductList());
// 2. 等待并获取结果，异常处理非常棘手
try {
String userInfo = userFuture.get(2, TimeUnit.SECONDS);
String productList = productFuture.get(2, TimeUnit.SECONDS);
// 3. 组合结果
return Map.of("user", userInfo, "products", productList);
} finally {
// 4. 必须手动关闭线程池
executor.shutdown();
}
}
// 模拟API调用...
}