我被CompletableFuture异常处理卡住了。
我的逻辑是发送电子邮件并保存此操作的状态。如果发送电子邮件抛出异常，我需要用异常消息保存状态。
public interface MyService {
CompletableFuture<Boolean> sendEmail(String content, String address);
CompletableFuture<StatusResult> saveStatus(String content, String address);}
处理器类目前有此代码。它工作正常，但对我来说并不优雅。我们如何摆脱用于在阶段之间共享状态的错误本地字段？
@Component
public class Processor {
private static final Logger LOGGER = LoggerFactory.getLogger(Processor.class);
@Autowired
private MyService myService;
public CompletableFuture<StatusResult> sendEmail(String content, String address) {
AtomicReference<String> error = new AtomicReference<>();// just to forward error message from exception block to thenCompose
return myService.sendEmail(content, address).exceptionally(e -> {
LOGGER.error("Exception during send email ", e);
error.set(e.getMessage());
return null;
}).thenCompose(x -> {
if (x == null) {
return myService.saveStatus(error.get(), address);
} else {
return myService.saveStatus("good", address);
}
});
}
}
看起来句柄方法应该会有所帮助，但它返回可完成未来的可完成未来
public CompletableFuture<StatusResult> sendEmail(String content, String address) {
CompletableFuture<CompletableFuture<StatusResult>> result = myService.sendEmail(content, address).handle((x, e) -> {
if (e != null) {
LOGGER.error("Exception during send email ", e);
return myService.saveStatus("error", address);
} else {
return myService.saveStatus("good", address);
}
});
}
您可以预先转换为保存状态。
public CompletableFuture<String> sendEmail(String content, String address) {
return myService.sendEmail(content, address)
.thenApply(b -> "good")
.exceptionally(Throwable::getMessage)
.thenCompose(status -> myService.saveStatus(status, address));
}
另一个可行的解决方案:
public CompletableFuture<StatusResult> sendEmailAndSaveStatus(String content, String address) {
CompletableFuture<Boolean> sendEmail = myService.sendEmail(content, address);
CompletableFuture<StatusResult> result = new CompletableFuture<>();
sendEmail.exceptionally(e -> {
LOGGER.info("Exception during send email ");
myService.saveStatus(e.getMessage(), address).thenApply(x -> result.complete(x));
return false;
});
sendEmail.thenCompose(x -> myService.saveStatus("good", address)).thenApply(x -> result.complete(x));
return result;
}
