java如何从Mono<Boolean>类型字段中提取值？

Question

我是java反应式的新手，我认为这是一件非常容易的事情

我的目的是评估返回Mono<Boolean>类型值的方法调用的结果，然后根据该结果确定操作过程。在下面的示例中，如果fieldAExists为true，我想运行在addFieldA方法的后半部分执行更新的代码

如何从Mono<Boolean>类型的值中提取布尔值？是否可以从Mono<Boolean>字段中提取值？我尝试使用subscribe（），但无法让它向我返回值

这两个被动语句可以组合成一个语句吗？感谢您提供的任何指导

public Mono<Boolean> addFieldA(Email email, String fieldA) {

    Mono<Boolean> fieldAExists = checkFieldAExistence(email);

    // if fieldAExists is true, call the below.
    return reactiveMongoTemplate.updateMulti(query(where("customer.email.address").is(email.address())),
            new Update().set("customer.publicId", fieldA), Account.class, accountCollection).map(result -> {
        if (result.wasAcknowledged()) {
            return true;
        } else {
            throw new IllegalArgumentException(
                    "Error adding fieldA value to customer with email address " + email.address());
        }
    });
}

public Mono<Boolean> checkFieldAExistence(Email email) {

    return reactiveMongoTemplate
            .findOne(query(where("customer.email.address").is(email.address()).and("customer.fieldA").ne(null)),
                    Account.class, accountCollection)
            .map(found -> true).switchIfEmpty(Mono.just(false));
}

Answer 1

您可以将它们与^{}组合，如下所示：

public Mono<Boolean> addFieldA(Email email, String fieldA) {

    return checkFieldAExistence(email).flatMap(fieldAExists -> {
        if (fieldAExists) {
            return reactiveMongoTemplate.updateMulti(query(where("customer.email.address").is(email.address())),
                    new Update().set("customer.publicId", fieldA), Account.class, accountCollection).map(result -> {
                if (result.wasAcknowledged()) {
                    return true;
                } else {
                    throw new IllegalArgumentException(
                            "Error adding fieldA value to customer with email address " + email.address());
                }
            });
        } else {
            return Mono.just(false);
        }
    });
}