java.net.UnknownHostException：6 次查询后无法解析“库存服务”[A(1)，AAAA(28)]

Question

我使用 Java 17、Spring Boot v3.1.3 和 Spring Cloud 堆栈来执行服务间通信。

当我向 http://localhost:8081/api/order 发出 POST 请求时收到此错误

订单服务错误：

    java.net.UnknownHostException: Failed to resolve 'inventory-service' [A(1), AAAA(28)] after 6 queries 
    at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1097) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:1044) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:432) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:662) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsResolveContext.access$500(DnsResolveContext.java:66) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:489) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:583) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:559) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:625) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:105) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsQueryContext.trySuccess(DnsQueryContext.java:317) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsQueryContext.finishSuccess(DnsQueryContext.java:309) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1392) ~[netty-resolver-dns-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[netty-codec-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:97) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
    at java.base/java.lang.Thread.run(Thread.java:1589) ~[na:na]

pom.xml

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            <version>4.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</artifactId>
            <version>3.1.6</version>
        </dependency>

WebClientConfig 类：

@Configuration
public class WebClientConfig {

    @Bean
    @LoadBalanced
    public WebClient.Builder webClientBuilder() {
        return WebClient.builder();
    }
}

订单服务类：

    private final WebClient.Builder webClientBuilder;

    public void placeOrder(OrderRequest orderRequest) {
        Order order = new Order();
        order.setOrderNumber(UUID.randomUUID().toString());

        List<OrderLineItems> orderLineItems = orderRequest.getOrderLineItemsDto()
                .stream()
                .map(this::mapToDto)
                .toList();
        order.setOrderLineItems(orderLineItems);

        List<String> skuCodes = order.getOrderLineItems().stream()
                .map(OrderLineItems::getSkuCode)
                .toList();

        InventoryResponse[] inventoryResponses = webClientBuilder.build().get()
                .uri("http://inventory-service/api/inventory",
                        uriBuilder -> uriBuilder.queryParam("skuCode", skuCodes).build())
                .retrieve()
                .bodyToMono(InventoryResponse[].class)
                .block();

应用程序属性：

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/order-service
spring.datasource.username=username
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=update
spring.application.name=order-service

server.port=8081

eureka.client.service-url.default-zone=http://localhost:8761/eureka
eureka.instance.prefer-ip-address=true
eureka.instance.hostname=localhost

库存服务中的 application.properties：

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3307/inventory-service
spring.datasource.username=root
spring.datasource.password=1234
spring.jpa.hibernate.ddl-auto=create-drop
spring.application.name=inventory-service

server.port=0

eureka.client.service-url.default-zone=http://localhost:8761/eureka

来自发现服务器的application.properties：

server.port=8761

eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.service-url.defaultZone=http://localhost:${server.port}/eureka/
eureka.instance.prefer-ip-address=true

我真的不知道我做错了什么。

Answer 1

我在github和stackoverflow找到了相同的解决方案，你也尝试一下：

HttpClient httpClient = HttpClient.create().resolver(DefaultAddressResolverGroup.INSTANCE); WebClient webClient = WebClient.builder().clientConnector(new ReactorClientHttpConnector(httpClient)).build();