后端服务oom

后端服务oom

• 问题描述
• 问题定位

问题描述

服务内部调用过程中会打印调用日志，日志内容过大导致oom，内存参数调大后还是不起作用，监控发现只用了4G

Caused by: java.lang.OutOfMemoryError: null
2025/8/1 21:03:17	at com.alibaba.fastjson2.JSONWriterUTF16.ensureCapacity(JSONWriterUTF16.java:1562)
2025/8/1 21:03:17	at com.alibaba.fastjson2.JSONWriterUTF16.writeStringEscape(JSONWriterUTF16.java:364)
2025/8/1 21:03:17	at com.alibaba.fastjson2.JSONWriterUTF16JDK8UF.writeString(JSONWriterUTF16JDK8UF.java:56)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.ObjectWriterImplMap.write(ObjectWriterImplMap.java:481)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.ObjectWriterImplList.write(ObjectWriterImplList.java:371)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.ObjectWriterImplMap.write(ObjectWriterImplMap.java:550)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.FieldWriterList.writeList(FieldWriterList.java:253)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.OWG_6_3_PageResponse.write(Unknown Source)
2025/8/1 21:03:17	at com.alibaba.fastjson2.writer.OWG_1_4_R.write(Unknown Source)
2025/8/1 21:03:17	at com.alibaba.fastjson2.JSON.toJSONString(JSON.java:2860)
2025/8/1 21:03:17	at com.sensetime.framework.feign.core.FeignResponseLogger.decode(FeignResponseLogger.java:47)
2025/8/1 21:03:17	at feign.InvocationContext.proceed(InvocationContext.java:36)
2025/8/1 21:03:17	at feign.AsyncResponseHandler.decode(AsyncResponseHandler.java:116)
2025/8/1 21:03:17	at feign.AsyncResponseHandler.handleResponse(AsyncResponseHandler.java:89)
2025/8/1 21:03:17	at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:141)
2025/8/1 21:03:17	at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:91)
2025/8/1 21:03:17	at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:100)
2025/8/1 21:03:17	at org.springframework.cloud.openfeign.FeignCachingInvocationHandlerFactory$1.proceed(FeignCachingInvocationHandlerFactory.java:66)
2025/8/1 21:03:17	at org.springframework.cache.interceptor.CacheInterceptor.lambda$invoke$0(CacheInterceptor.java:54)
2025/8/1 21:03:17	at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:351)
2025/8/1 21:03:17	at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:64)
2025/8/1 21:03:17	at org.springframework.cloud.openfeign.FeignCachingInvocationHandlerFactory.lambda$create$1(FeignCachingInvocationHandlerFactory.java:53)
2025/8/1 21:03:17	at com.sun.proxy.$Proxy140.queryConversationById(Unknown Source)

问题定位

由于调用别的服务返回了太大的数据，然后在用 Fastjson2 做序列化时内存爆了。

增加了黑名单接口，只有这个接口error才会打印日志

问题解决！！！

@Slf4j
public class FeignResponseLogger implements Decoder {

    private final List<PropertyFilter> propertyFilters;

    final Decoder delegate;

    public FeignResponseLogger(List<PropertyFilter> propertyFilters, Decoder delegate) {
        Objects.requireNonNull(delegate, "Decoder must not be null. ");
        this.delegate = delegate;
        this.propertyFilters = propertyFilters;
    }

    // 黑名单接口（只在非 200 时打印）
    private static final List<String> URL_ONLY_ERROR_LOGGING = Arrays.asList(
            "/xxx/xxx/xxx"
    );

    private boolean isOnlyErrorLogUrl(String url) {
        return URL_ONLY_ERROR_LOGGING.stream().anyMatch(url::contains);
    }


    @Override
    public Object decode(Response response, Type type) throws IOException, DecodeException, FeignException {
        try {
            Object decodedObject = delegate.decode(response, type);

            String url = response.request().url();
            int status = response.status();
            boolean isOnlyLogOnError = isOnlyErrorLogUrl(url);

            // 判断是否需要打印日志
            if (!isOnlyLogOnError || status != 200) {
                String decodedBody;
                try {
                    if (decodedObject instanceof ResponseEntity) {
                        decodedBody = "Http response";
                    } else {
                        decodedBody = JSON.toJSONString(decodedObject, propertyFilters.toArray(new PropertyFilter[0]));
                    }
                } catch (Exception e) {
                    log.warn("json serialize error|msg={}", e.getMessage(), e);
                    decodedBody = "parse error";
                }

                Long costTime = FeignRequestLogger.getCurrentRequestContext()
                        .map(FeignRequestLogger.Context::getStartTime)
                        .map(startTime -> System.currentTimeMillis() - startTime)
                        .orElse(null);

                String logPrefix = (status == 200 ? "info" : "error");
                logAtLevel(logPrefix, "feign request {}|cost={}|url={}|status={}|body={}",
                        logPrefix, costTime, url, status,
                        decodedBody.length() > 100 ? decodedBody.substring(0, 100) + "..." : decodedBody);
            }

            return decodedObject;
        } finally {
            FeignRequestLogger.clearCurrentRequestContext();
        }
    }
    private void logAtLevel(String level, String format, Object... args) {
        switch (level) {
            case "info":
                log.info(format, args);
                break;
            case "warn":
                log.warn(format, args);
                break;
            case "error":
                log.error(format, args);
                break;
            default:
                log.debug(format, args);
                break;
        }
    }


}