kotlin：期待menber声明，而我似乎已经这样做了

ejk8hzay  于 2021-07-11  发布在  Java
关注(0)|答案(1)|浏览(616)

我发现了一些带有相同错误信息的问题，但据我所知，我已经正确地声明了它。
以下是kotlin的全部代码：

  1. package com.mybank.service
  3. import org.reactivestreams.Publisher
  4. import com.mongodb.client.result.InsertOneResult
  5. import com.mongodb.reactivestreams.client.MongoClients
  6. import com.mongodb.reactivestreams.client.MongoClient
  7. import com.mongodb.reactivestreams.client.MongoCollection
  8. import com.mongodb.reactivestreams.client.MongoDatabase
  9. import java.util.Arrays
  10. import org.bson.Document
  12. class test {
  14.     //MongoClient mongoClient = MongoClients.create();
  15.     var mongoClient: MongoClient = MongoClients.create("mongodb://root:q@localhost:27017")
  16.     var database: MongoDatabase = mongoClient.getDatabase("mydb")
  17.     var collection: MongoCollection<Document> = database.getCollection("mycollection")
  19.     var doc: Document = Document("name", "MongoDB")
  20.             .append("type", "database")
  21.             .append("count", 1)
  22.             .append("versions", Arrays.asList("v3.2", "v3.0", "v2.6"))
  23.             .append("info", Document("x", 203).append("y", 102))
  25.     //publisher decalred and initialized
  26.     var publisher: Publisher<InsertOneResult> = collection.insertOne(doc)
  28.     publisher***why publisher isn't initialized yet???

它在java中就是这样工作的

  1. imports ommited, same as above
  2. public class App {
  3.     public static void main(String[] args) throws Throwable {
  5.         //MongoClient mongoClient = MongoClients.create();
  6.         MongoClient mongoClient = MongoClients.create("mongodb://root:q@localhost:27017");
  7.         MongoDatabase database = mongoClient.getDatabase("mydb");
  8.         MongoCollection<Document> collection = database.getCollection("mycollection");
  10.         Document doc = new Document("name", "MongoDB")
  11.                 .append("type", "database")
  12.                 .append("count", 1)
  13.                 .append("versions", Arrays.asList("v3.2", "v3.0", "v2.6"))
  14.                 .append("info", new Document("x", 203).append("y", 102));
  16.         Publisher<InsertOneResult> publisher = collection.insertOne(doc);
  18.         publisher.subscribe(new Subscriber<InsertOneResult>() {
  19.             @Override
  20.             public void onSubscribe(final Subscription s) {
  21.                 s.request(1);  // <--- Data requested and the insertion will now occur
  22.             }
  24.             @Override
  25.             public void onNext(final InsertOneResult result) {
  26.                 System.out.println("Inserted: " + result);
  27.             }
  29.             @Override
  30.             public void onError(final Throwable t) {
  31.                 System.out.println("Failed");
  32.             }
  34.             @Override
  35.             public void onComplete() {
  36.                 System.out.println("Completed");
  37.             }
  38.         });
  40.         //all examples
  41.         collection.countDocuments()
  42.                 .subscribe(new SubscriberHelpers.PrintSubscriber<Long>("total # of documents after inserting "
  43.                         + " is: %s"));
  45.         collection.find(eq("name", "MongoDB")).first().subscribe(new SubscriberHelpers.PrintDocumentSubscriber());
  47.         Thread.sleep(1000);
  49.     }
  51. }

错误消息：

我不是为android编写代码，这里是build.gradle，尽管我认为它不相关

  1. plugins {
  2.     id "org.jetbrains.kotlin.jvm" version "1.3.72"
  3.     id "org.jetbrains.kotlin.kapt" version "1.3.72"
  4.     id "org.jetbrains.kotlin.plugin.allopen" version "1.3.72"
  5.     id "application"
  6.     id 'com.google.protobuf' version '0.8.13'
  7. }
  9. version "0.2"
  10. group "account-control"
  12. repositories {
  13.     mavenLocal()
  14.     jcenter()
  15. }
  17. configurations {
  18.     // for dependencies that are needed for development only
  19.     developmentOnly
  20. }
  22. dependencies {
  23.     kapt(enforcedPlatform("io.micronaut:micronaut-bom:$micronautVersion"))
  24.     kapt("io.micronaut:micronaut-inject-java")
  25.     kapt("io.micronaut:micronaut-validation")
  27.     implementation(enforcedPlatform("io.micronaut:micronaut-bom:$micronautVersion"))
  28.     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:${kotlinVersion}")
  29.     implementation("org.jetbrains.kotlin:kotlin-reflect:${kotlinVersion}")
  30.     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinxCoroutinesVersion")
  31.     implementation("io.micronaut:micronaut-runtime")
  32. //    implementation("io.micronaut.grpc:micronaut-grpc-runtime")
  33.     implementation("io.micronaut.grpc:micronaut-grpc-server-runtime:$micronautGrpcVersion")
  34.     implementation("io.micronaut.grpc:micronaut-grpc-client-runtime:$micronautGrpcVersion")
  35.     implementation("io.grpc:grpc-kotlin-stub:${grpcKotlinVersion}")
  37.     //Kafka
  38.     implementation("io.micronaut.kafka:micronaut-kafka")
  40.     //vertx
  41.     implementation("io.micronaut.sql:micronaut-vertx-mysql-client")
  42.     //implementation("io.micronaut.configuration:micronaut-vertx-mysql-client")
  43.     compile 'io.vertx:vertx-lang-kotlin:3.9.4'
  45.     //mongodb
  46.     implementation("org.mongodb:mongodb-driver-reactivestreams:4.1.1")
  48.     runtimeOnly("ch.qos.logback:logback-classic:1.2.3")
  49.     runtimeOnly("com.fasterxml.jackson.module:jackson-module-kotlin:2.9.8")
  51.     kaptTest("io.micronaut:micronaut-inject-java")
  53.     testImplementation enforcedPlatform("io.micronaut:micronaut-bom:$micronautVersion")
  54.     testImplementation("org.junit.jupiter:junit-jupiter-api:5.3.0")
  55.     testImplementation("io.micronaut.test:micronaut-test-junit5")
  56.     testImplementation("org.mockito:mockito-junit-jupiter:2.22.0")
  58.     testRuntime("org.junit.jupiter:junit-jupiter-engine:5.3.0")
  59.     testRuntime("org.jetbrains.spek:spek-junit-platform-engine:1.1.5")
  60. }
  62. test.classpath += configurations.developmentOnly
  64. mainClassName = "account-control.Application"
  66. test {
  67.     useJUnitPlatform()
  68. }
  70. allOpen {
  71.     annotation("io.micronaut.aop.Around")
  72. }
  74. compileKotlin {
  75.     kotlinOptions {
  76.         jvmTarget = '11' 
  77.         //Will retain parameter names for Java reflection
  78.         javaParameters = true 
  79.     }
  80. }
  81. //compileKotlin.dependsOn(generateProto)
  83. compileTestKotlin {
  84.     kotlinOptions {
  85.         jvmTarget = '11' 
  86.         javaParameters = true 
  87.     }
  88. }
  90. tasks.withType(JavaExec) {
  91.     classpath += configurations.developmentOnly
  92.     jvmArgs('-XX:TieredStopAtLevel=1', '-Dcom.sun.management.jmxremote')
  93. }
  95. sourceSets {
  96.     main {
  97.         java {
  98.             srcDirs 'build/generated/source/proto/main/grpc'
  99.             srcDirs 'build/generated/source/proto/main/grpckt'
  100.             srcDirs 'build/generated/source/proto/main/java'
  101.         }
  102.     }
  103. }
  105. protobuf {
  106.     protoc { artifact = "com.google.protobuf:protoc:${protocVersion}" }
  107.     plugins {
  108.         grpc { artifact = "io.grpc:protoc-gen-grpc-java:${grpcVersion}" }
  109.         grpckt { artifact = "io.grpc:protoc-gen-grpc-kotlin:${grpcKotlinVersion}" }
  110.     }
  111.     generateProtoTasks {
  112.         all()*.plugins {
  113.             grpc {}
  114.             grpckt {}
  115.         }
  116.     }
  117. }

***编辑

  1. package com.mybank.service
  3. import org.reactivestreams.Publisher
  4. import com.mongodb.client.result.InsertOneResult
  5. import com.mongodb.reactivestreams.client.MongoClients
  6. import com.mongodb.reactivestreams.client.MongoClient
  7. import com.mongodb.reactivestreams.client.MongoCollection
  8. import com.mongodb.reactivestreams.client.MongoDatabase
  9. import java.util.Arrays
  10. import org.bson.Document
  11. import javax.inject.Singleton
  13. class test {
  15.     //MongoClient mongoClient = MongoClients.create();
  16.     var mongoClient: MongoClient = MongoClients.create("mongodb://root:q@localhost:27017")
  17.     var database: MongoDatabase = mongoClient.getDatabase("mydb")
  18.     var collection: MongoCollection<Document> = database.getCollection("mycollection")
  20.     var doc: Document = Document("name", "MongoDB")
  21.             .append("type", "database")
  22.             .append("count", 1)
  23.             .append("versions", Arrays.asList("v3.2", "v3.0", "v2.6"))
  24.             .append("info", Document("x", 203).append("y", 102))
  26.     //publisher decalred and initialized
  27.     var publisher: Publisher<InsertOneResult> = collection.insertOne(doc)
  28. }

然后在另一节课上

  1. @Singleton
  2. class TransactionService(){
  4.     @Inject
  5.     lateinit var test: test
  7.     fun postDebitTransaction(debit: String) : String{
  9.         test.publisher.subscribe(
  10.                 object x: Subscriber<InsertOneResult> {
  11.                     override fun onSubscribe(s: Subscription) {
  12.                         s.request(1) // <--- Data requested and the insertion will now occur
  13.                     }
  15.                     override fun onNext(result: InsertOneResult) {
  16.                         println("Inserted: $result")
  17.                     }
  19.                     override fun onError(t: Throwable) {
  20.                         println("Failed")
  21.                     }
  23.                     override fun onComplete() {
  24.                         println("Completed")
  25.                     }
  26.                 })
  28.         return "posted"
  29.     }
  30. }

而我正在
类型不匹配。必需：订阅服务器<in insertoneresult！>！
我确信我在Kotlin犯了些愚蠢的错误

JavaLambdakotlinkotlin-coroutines

1条答案

按热度按时间
vlurs2pr

vlurs2pr1#

编译器并没有告诉您成员没有初始化，而是告诉您，如果函数不是成员声明的一部分，就不允许调用类主体中的函数。
例如

  1. class Foo {
  2.     // not allowed
  3.     3.toString()
  4. }
  6. class Bar {
  7.     // prefectly fine
  8.     val three = 3.toString()
  9. }

java也有同样的行为。java示例之所以能够工作，是因为您的代码在 main 方法而不是类主体。

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