scala doobie没有将值插入数据库

kuarbcqp  于 2021-07-14  发布在  Java
关注(0)|答案(1)|浏览(292)

我要插入值的代码是:

def insert(link: entity.Link) : IO[Int] = {
    logger.info("Inserting link: " + link.toString())
    sql"insert into links (title,url,publication_date,feed_id) values (${link.getTitle},${link.getUrl},${link.getPublicationDate},${link.getFeed.getId})"
        .update
        .run
        .transact(transactor)
}

调用它的方法是:

val links = for{
        feeds <- getFeeds()
        ls: List[Link] = feeds.flatMap(rssFeedReader.readFeedItems(_).asScala)

        ios = ls.map(
            link => 
                linkPersistence
                    .countByUrl(link.getUrl())
                    .map(x => if(x==0) linkPersistence.insert(link) else identity(x))

        )

        s <- ios.sequence
    }yield(s)
    val result = links.unsafeRunSync()
    logger.info("Result: " + result.toString())

不幸的是,我不能用于表达,因为 IO 没有 withFilter 我在maven项目中(我正在将spring启动应用程序迁移到typelevel堆栈),所以我不能使用改进的for expressions sbt插件。
我的问题是没有将行插入数据库。日志上有:

reddit_bot_1  | 2021-04-23 13:06:57.805  INFO 1 --- [text-global-167] r.i.repository.LinkPersistence           : Inserting link: Link{id=0, feed=Feed{id=79, url='https://ytali.com/feed/'}, title='Se il grillo non fosse stato parlante', url='https://ytali.com/2021/04/21/se-il-grillo-non-fosse-stato-parlante/', publicationDate=Wed Apr 21 11:12:59 GMT 2021}
reddit_bot_1  | 2021-04-23 13:06:57.838  INFO 1 --- [text-global-167] r.i.repository.LinkPersistence           : Inserting link: Link{id=0, feed=Feed{id=82, url='https://cronacheletterarie.com/feed/'}, title='Scrivere come in una serie tv', url='https://www.cronacheletterarie.com/2021/04/22/scrivere-come-in-una-serie-tv-due-nuovi-thriller-italiani/', publicationDate=Thu Apr 22 06:50:30 GMT 2021}
reddit_bot_1  | 2021-04-23 13:06:57.993  INFO 1 --- [nio-8080-exec-1] reddit_bot.service.LinkUpdater           : Result: List(1, 1, 1, 1, 1, 1, 1, IO$970148716, IO$398844220, IO$2051359159, IO$1102460161, IO$1646104176, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$1525243662, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$183629085, IO$2057291647, IO$1962915922, IO$1686018284, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$1629671523, IO$1703036679, IO$1823891149, IO$2090799695, IO$189359223, IO$2089070694, IO$572184845, IO$638827115, IO$1723402242, IO$1063752499, IO$1262614371, IO$1882901634, IO$1592599455, IO$1561386362, IO$422495060, IO$1071010351, IO$135298961, IO$1395689700, IO$1022084533, IO$824291117, IO$977707631, IO$1835432555, IO$264428575, IO$858145293, IO$1014815708, IO$1654086426, IO$2074886515, IO$2048606753, IO$551801989, IO$2029261832, IO$1640654268, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$1096825326, IO$2132380347, IO$664110340, IO$364966863, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$1429149648, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, IO$1724908444, IO$1835403239, IO$2133511951, IO$1385617069, IO$876405632, IO$1773704159, IO$1078164304, IO$604307019, IO$2004298152, 1, IO$1526495986, 1, 1, 1, 1, 1, 1, 1, 1, 1)

事务处理程序的创建方式如下:

def transactor() = Transactor.fromDriverManager[IO](
  "com.mysql.cj.jdbc.Driver",
  "jdbc:mysql://database:3306/redditbot",
  "redditbot",
  "redditbot"
)

更新
正如@luis miguel mej所建议的í阿苏á我修改了我的 pom.xml 文件如下:

<plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>scala-maven-plugin</artifactId>
            <version>4.4.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>testCompile</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <scalaVersion>${scala.version}</scalaVersion>
                <sourceDir>src/main/scala</sourceDir>
                <compilerPlugins>
                    <compilerPlugin>
                        <groupId>com.olegpy</groupId>
                        <artifactId>better-monadic-for_2.13</artifactId>
                        <version>0.3.1</version>
                    </compilerPlugin>
                </compilerPlugins>
            </configuration>
        </plugin>

但问题依然存在。

laik7k3q

laik7k3q1#

作者@luismiguelmejí华硕á雷兹
正如错误明确指出的,io没有 withFilter 方法(你可以在这里查看scaladoc)。当您显式地放置类型时,您基本上是在过滤与该类型匹配的所有元素。而且,由于该方法不存在,因此不会编译。-不,我不知道有什么解决办法。
但是,我至少可以想一个理由,为什么它不应该有它。io并不像list那样完全是一个元素的“容器”,因为它只是一个计算的描述,如果你想把它看作一个容器,它将只有一个元素,比如option。但是,与前者不同的是,没有空io的概念。因此,过滤io是没有意义的。
我发现的解决方法是将过滤器移动到另一个函数中:

def insertIfNotPresent(link: Link, foundLinksCount: Int): IO[Option[Int]] = 
    foundLinksCount match{
        case 0 => linkPersistence.insert(link).map(Option(_))
        case _ => IO.pure(None)
    }

调用代码变为:

for{
  foundLinksCount: Int <- linkPersistence.countByUrl(link.getUrl())
  n: Option[Int] <- insertIfNotPresent(link, foundLinksCount)
}yield(n)

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