后端服务oom

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);}@Overridepublic 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;}}}