public class SpringbootWebApplicationTests {
private final Logger logger = LoggerFactory.getLogger(SpringbootWebApplicationTests.class);
private static final ExecutorService threadPool = Executors.newFixedThreadPool(5);
@Test
public void testCompletableFuture() throws Exception {
// 1、第一组
CompletableFuture.runAsync(() -> {
logger.info("runAsync--无返回值");
});
CompletableFuture.runAsync(() -> {
logger.info("runAsync--无返回值--指定线程池");
}, threadPool);
// 2、第二组
CompletableFuture supplyAsync1 = CompletableFuture.supplyAsync(() -> {
logger.info("supplyAsync--有返回值");
return 1;
});
CompletableFuture supplyAsync2 = CompletableFuture.supplyAsync(() -> {
logger.info("supplyAsync--有返回值--指定线程池");
return 1;
}, threadPool);
// 3，任务回调
// 3.1
// thenApply和他的父任务在一个线程里
CompletableFuture thenApply1 = supplyAsync1.thenApply((result) -> {
logger.info("thenApply:supplyAsync1执行完毕后的回调，参数为supplyAsync1任务的返回值");
return "result:" + result;
});
// thenApplyAsync和他的父任务可能不在一个线程里
CompletableFuture thenApply2 = supplyAsync2.thenApplyAsync((result) -> {
logger.info("thenApplyAsync:supplyAsync2执行完毕后的回调，参数为supplyAsync2任务的返回值");
return "result:" + result;
});
// 可以指定线程池
CompletableFuture thenApply3 = supplyAsync2.thenApplyAsync((result) -> {
logger.info("thenApplyAsync--指定线程池:supplyAsync2执行完毕后的回调，参数为supplyAsync2任务的返回值");
return "result:" + result;
}, threadPool);
// 3.2
CompletableFuture thenAccept = thenApply1.thenAccept((result) -> {
logger.info("thenAccept:thenApply1执行完毕后的回调，参数为thenApply1任务的返回值，没有返回值");
int i = 1 / 0;
});
CompletableFuture thenRun = thenApply2.thenRun(() -> {
logger.info("thenRun:thenApply2执行完毕后的回调，没有参数，也没有返回值");
});
// 3.3
thenAccept.exceptionally((exception) -> {
logger.info("exceptionally:任务异常后的回调，参数为异常信息");
logger.info("异常信息", exception);
return null;
});
thenApply3.whenComplete((result, exception) -> {
logger.info("{},{}", result, exception);
logger.info("whenComplete:任务异常后的回调，会将执行结果或者执行期间抛出的异常传递给回调方法，如果是正常执行则异常为null");
});
thenApply3.whenCompleteAsync((result, exception) -> {
logger.info("{},{}", result, exception);
logger.info("whenCompleteAsync:任务异常后的回调，会将执行结果或者执行期间抛出的异常传递给回调方法，如果是正常执行则异常为null");
});
thenApply3.whenCompleteAsync((result, exception) -> {
logger.info("{},{}", result, exception);
logger.info("whenCompleteAsync--指定线程池:任务异常后的回调，会将执行结果或者执行期间抛出的异常传递给回调方法，如果是正常执行则异常为null");
}, threadPool);
logger.info("supplyAsync获取返回值:" + supplyAsync1.get() + "--" + supplyAsync2.get());
logger.info("thenApply获取返回值:" + thenApply1.get() + "--" + thenApply2.get() + "--" + thenApply3.get());
}
}
Original: https://www.cnblogs.com/lm66/p/15847218.html
Author: Liming_Code
Title: CompletableFuture方法全解
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