英文:
spring webflux all api's giving UnsupportedMediaTypeException
问题
我有一个`@SpringBootApplication`，使用Gson而不是Jackson，以下是使用以下转换器的代码：
```java
@Configuration
public class ApplicationConfiguration {
@Bean
public GsonBuilder gsonBuilder(){
final GsonBuilder gsonBuilder = new GsonBuilder();
// 在这里注册TypeAdapter
return gsonBuilder;
}
}
现在我有一个控制器（所有控制器都会失败，不仅是这个，但它们的语法相同）：
@RestController("/1/api/release/")
@Log
@RequiredArgsConstructor
public class ReleaseController {
@PostMapping("blocked")
public Mono<ServerResponse> issueIsBlocked() {
return Mono.just("test")
.flatMap(s -> ServerResponse.ok().bodyValue(s))
.onErrorResume(Throwable.class, e -> ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).bodyValue(e.getMessage()));
}
}
而且application.properties包含：
spring.http.converters.preferred-json-mapper=gson
spring.codec.max-in-memory-size=10MB
然而，我得到了这个错误：
org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/json' not supported for bodyType=java.util.LinkedHashMap<?, ?>
我的pom.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>testing</artifactId>
<packaging>pom</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.5.RELEASE</version>
</parent>
<groupId>com.dummy</groupId>
<version>0.0.1-SNAPSHOT</version>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<!-- 排除默认的Jackson依赖 -->
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-json</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.9</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
我注意到的事情：
- 错误出现在我的方法被调用之前，因此与在方法中指定的错误处理无关。
- 我尝试为LinkedHashMap添加类型适配器，但仍未被捕获。不过，如果需要的话，我目前只为WebClient添加了它们，但未考虑Spring如何处理转换。我在这里只是猜测，但我认为它会使用我在配置中指定的Gson bean。
- 如果我查看
BodyInserters:376中的context.messageWriters()，我看不到我明确添加的任何熟悉的内容。
我该如何使我的API正常工作？
<details>
<summary>英文:</summary>
I have a `@SpringBootApplication` using Gson instead of jackson with the following converter:
@Configuration
public class ApplicationConfiguration {
@Bean
public GsonBuilder gsonBuilder(){
final GsonBuilder gsonBuilder = new GsonBuilder();
// I registerTypeAdapter 's here
return gson;
}
}
I now have my controller (this fails on all of them not just this but they are the same syntax)
@RestController("/1/api/release/")
@Log
@RequiredArgsConstructor
public class ReleaseController {
@PostMapping("blocked")
public Mono<ServerResponse> issueIsBlocked() {
return Mono.just("test")
.flatMap(s -> ServerResponse.ok().bodyValue(s))
.onErrorResume(Throwable.class, e -> ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).bodyValue(e.getMessage()));
}
}
And application.properties contains
spring.http.converters.preferred-json-mapper=gson
spring.codec.max-in-memory-size=10MB
I however get this error
org.springframework.web.reactive.function.UnsupportedMediaTypeException: Content type 'application/json' not supported for bodyType=java.util.LinkedHashMap<?, ?>
at org.springframework.web.reactive.function.BodyInserters.unsupportedError(BodyInserters.java:391)
at org.springframework.web.reactive.function.BodyInserters.lambda$writeWithMessageWriters$11(BodyInserters.java:381)
at java.base/java.util.Optional.orElseGet(Optional.java:369)
at org.springframework.web.reactive.function.BodyInserters.writeWithMessageWriters(BodyInserters.java:381)
at org.springframework.web.reactive.function.BodyInserters.lambda$fromValue$1(BodyInserters.java:98)
at org.springframework.web.reactive.function.server.DefaultServerResponseBuilder$BodyInserterResponse.writeToInternal(DefaultServerResponseBuilder.java:409)
at org.springframework.web.reactive.function.server.DefaultServerResponseBuilder$AbstractServerResponse.writeTo(DefaultServerResponseBuilder.java:351)
at org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler.write(AbstractErrorWebExceptionHandler.java:311)
at org.springframework.boot.autoconfigure.web.reactive.error.AbstractErrorWebExceptionHandler.lambda$handle$2(AbstractErrorWebExceptionHandler.java:264)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:118)
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:203)
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1705)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:144)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2075)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:1949)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
at reactor.core.publisher.Operators.complete(Operators.java:135)
at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:97)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:100)
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onError(FluxOnAssembly.java:390)
at reactor.core.publisher.Operators.error(Operators.java:185)
at reactor.core.publisher.MonoError.subscribe(MonoError.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:97)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:165)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.secondError(MonoFlatMap.java:185)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onError(MonoFlatMap.java:251)
at reactor.core.publisher.Operators$MonoSubscriber.onError(Operators.java:1752)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreInner.onError(MonoIgnoreThen.java:235)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:165)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onError(Operators.java:1944)
at reactor.core.publisher.Operators.error(Operators.java:185)
at reactor.core.publisher.MonoError.subscribe(MonoError.java:52)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onComplete(MonoFlatMap.java:174)
at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:96)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:359)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:211)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:121)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:162)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2075)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:1949)
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onSubscribe(FluxMapFuseable.java:90)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:211)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.netty.http.server.HttpServerHandle.onStateChange(HttpServerHandle.java:64)
at reactor.netty.tcp.TcpServerBind$ChildObserver.onStateChange(TcpServerBind.java:228)
at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:465)
at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:90)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:170)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:321)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:295)
at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:834)
my pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>testing</artifactId>
<packaging>pom</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.5.RELEASE</version>
</parent>
<groupId>com.dummy</groupId>
<version>0.0.1-SNAPSHOT</version>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<!-- Exclude the default Jackson dependency -->
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-json</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.9</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
things i have noticed:
- the error appears before my method is even entered, so it shouldn't really have anything to do with error handling specified there.
- I tried adding type adapters for LinkedHashMap however they were still not caught. However if this is what is needed, I am currently only adding them for the WebClient not however spring is handling conversion. I am simply guessing here however I would assume it took the GSON bean i specified in my configuration, in which case it would be there.
- If i look at BodyInserters:376 context.messageWriters() I see nothing familiar to stuff I added explicitly.
How can I get my api's to work?
</details>
# 答案1
**得分**: 2
你不应该在控制器中使用 `Mono<ServerReponse>`，因为它似乎没有被任何序列化器正确映射。
有两种替代方案：
1. 使用响应实体
```java
@PostMapping("blocked")
public Mono<ResponseEntity<String>> issueIsBlocked() {
return Mono.just("test")
.map(s -> new ResponseEntity<>(s, HttpStatus.OK))
.onErrorResume(Throwable.class,
e -> Mono.just(new ResponseEntity<>(e.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR))
);
}
- 使用 WebFlux 提供的 RouterFunction
@Configuration
public class RouterConfig {
@Bean
RouterFunction<ServerResponse> home() {
return route(POST("/blocked"),
request -> Mono.just("test")
.flatMap(s -> ServerResponse.ok().bodyValue(s))
.onErrorResume(Throwable.class, e ->
ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).bodyValue(e.getMessage())
));
}
}
英文:
You are not supposed to use Mono<ServerReponse> in controllers, as such it doesn't appear to be mapped correctly by any serializer.
There are two alternatives
-
Use response entity
@PostMapping("blocked") public Mono<ResponseEntity<String>> issueIsBlocked() { return Mono.just("test") .map(s -> new ResponseEntity<>(s, HttpStatus.OK)) .onErrorResume(Throwable.class, e -> Mono.just(new ResponseEntity<>(e.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR)) ); }
2.Use the RouterFunction provided by webflux
@Configuration
public class RouterConfig {
@Bean
RouterFunction<ServerResponse> home() {
return route(POST("/blocked"),
request -> Mono.just("test")
.flatMap(s -> ServerResponse.ok().bodyValue(s))
.onErrorResume(Throwable.class, e ->
ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).bodyValue(e.getMessage())
));
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
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