报错信息

org.springframework.core.io.buffer.DataBufferLimitException: Exceeded limit on max bytes to buffer : 262144
        at org.springframework.core.io.buffer.LimitedDataBufferList.raiseLimitException(LimitedDataBufferList.java:99)
        Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
        *__checkpoint ? springfox.boot.starter.autoconfigure.SwaggerUiWebFluxConfiguration$CustomWebFilter [DefaultWebFilterChain]
        *__checkpoint ? org.springframework.web.cors.reactive.CorsWebFilter [DefaultWebFilterChain]
        *__checkpoint ? org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
        *__checkpoint ? org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
Original Stack Trace:
                at org.springframework.core.io.buffer.LimitedDataBufferList.raiseLimitException(LimitedDataBufferList.java:99)
                at org.springframework.core.io.buffer.LimitedDataBufferList.updateCount(LimitedDataBufferList.java:92)
                at org.springframework.core.io.buffer.LimitedDataBufferList.add(LimitedDataBufferList.java:58)
                at reactor.core.publisher.MonoCollect$CollectSubscriber.onNext(MonoCollect.java:119)
                at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
                at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:200)
                at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
                at reactor.netty.channel.FluxReceive.onInboundNext(FluxReceive.java:364)
                at reactor.netty.channel.ChannelOperations.onInboundNext(ChannelOperations.java:404)
                at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:595)
                at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:93)

private void updateCount(int bytesToAdd) {
    if (this.maxByteCount < 0) {
       return;
    }
    if (bytesToAdd > Integer.MAX_VALUE - this.byteCount) {
       raiseLimitException();
    }
    else {
       this.byteCount += bytesToAdd;
       if (this.byteCount > this.maxByteCount) {
          raiseLimitException(); //报错地方
       }
    }
}

spring:

codec:

max-in-memory-size: 20MB 这个配置未生效。

检查拦截Request的代码filter：

public GatewayFilter apply(Object config) {
    return (exchange, chain) -> {
        if (HttpMethod.GET.matches(exchange.getRequest().getMethodValue())
                || HttpMethod.POST.matches(exchange.getRequest().getMethodValue())) {
            ModifyRequestBodyGatewayFilterFactory.Config modifyRequestConfig = new ModifyRequestBodyGatewayFilterFactory.Config()
                    .setContentType(ContentType.APPLICATION_JSON.getMimeType())
                    .setRewriteFunction(String.class, String.class, (exchange1, originalRequestBody) -> {
                       //业务逻辑
                            return Mono.just(dataStr);
                        } catch (Exception e) {
                            return Mono.error(e);
                        }
                    });

            return new ModifyRequestBodyGatewayFilterFactory()//这个地方出问题了
                    .apply(modifyRequestConfig)
                    .filter(exchange, chain)
                    .onErrorResume(e -> handleFilterError(exchange, e));
        }

        return chain.filter(exchange);
    };
}

ModifyRequestBodyGatewayFilterFactory（）这个构造底层实现如下

public ModifyRequestBodyGatewayFilterFactory() {
    super(Config.class);
    this.messageReaders = HandlerStrategies.withDefaults().messageReaders();
}

底层默认值：

修改方式

使用这个来构造并且引入以下bean，使得配置生效

@Autowired

ServerCodecConfigurer codecConfigurer;

spring.codec.max-in-memory-size配置说明

spring.codec.max-in-memory-size是Spring WebFlux中的一个配置参数，用于限制内存中的数据缓冲区大小。具体解释如下：

1. 作用：控制在处理请求或响应时，Spring WebFlux使用的内存缓冲区的最大大小。用于防止应用程序因为大量数据导致内存消耗过高而崩溃。
2. 配置方式：以字节为单位指定缓冲区的最大大小。可以在应用程序的配置文件（如application.properties或application.yml）中设置该参数。
3. 默认值：如果未显式配置，则默认值为262144字节（即256KB）。

底层生效逻辑在类：CodecsAutoConfiguration

@Bean
@Order(0)
CodecCustomizer defaultCodecCustomizer(CodecProperties codecProperties) {
    return (configurer) -> {
       PropertyMapper map = PropertyMapper.get();
       CodecConfigurer.DefaultCodecs defaultCodecs = configurer.defaultCodecs();
       defaultCodecs.enableLoggingRequestDetails(codecProperties.isLogRequestDetails());
       map.from(codecProperties.getMaxInMemorySize()).whenNonNull().asInt(DataSize::toBytes)
             .to(defaultCodecs::maxInMemorySize);
    };
}