1、性能优化临时处理方案使用Spring @Cacheable注解
1.1、随着服务器的QPS值的提高，导致很多用户在我们项目多个页面数据加载很慢。在赶别的版本临时使用Spring @Cacheable注解以及Redis做了常调接口以及短期变动不大接口的响应缓存。出现了以下BUG做个解决记录方案。
1.2、获取缓存异常：java.util.LinkedHashMap cannot be cast to XXX.XXX
代码语言：javascript复制/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释
* 2021-11-16 18:17:27,225 ERROR com.zhili.common.controller.BaseController - [39] - java.util.LinkedHashMap cannot be cast to com.zhili.common.result.ResultListBo2021-11-16 18:17:27,225 ERROR com.zhili.common.controller.BaseController - [39] - java.util.LinkedHashMap cannot be cast to com.zhili.common.result.ResultVo2021-11-16 18:17:27,225 ERROR com.zhili.common.controller.BaseController - [39] - java.util.LinkedHashMap cannot be cast to com.zhili.common.result.ResultListVo2021-11-16 18:17:27,229 ERROR com.zhili.common.exception.ExceptionHandler - [37] - Exception -- 500 >java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.zhili.common.result.ResultVo at com.zhili.kanli.controller.talent.TalentUserController$$EnhancerBySpringCGLIB$$ac8b3bc0.getTalentUserCenter(<generated>) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:503) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:590) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:760) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1617) at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:226) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:108) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:536) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1592) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1296) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1562) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1211) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.Server.handle(Server.java:500) at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:386) at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:562) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:378) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:388) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806) at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938) at java.lang.Thread.run(Thread.java:748)
*/1.3、根据报错结果显示就是获取缓存的时候转换成我们自己定义的Object出现了错误。于是便检查新增处理缓存的方法。
代码语言：javascript复制private RedisCacheConfiguration getRedisCacheConfigurationWithTtl(Integer seconds) { // 设置 json 序列化 Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class); ObjectMapper om = new ObjectMapper(); om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY); jackson2JsonRedisSerializer.setObjectMapper(om); RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig(); redisCacheConfiguration = redisCacheConfiguration.serializeValuesWith( RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer)). // 设置过期时间 entryTtl(Duration.ofSeconds(seconds)); return redisCacheConfiguration;}出现这种异常，需要向自定义ObjectMapper，设置一些参数，而不是直接使用Jackson2JsonRedisSerializer类中黙认的ObjectMapper，看源代码可以知道，Jackson2JsonRedisSerializer中的ObjectMapper是直接使用new ObjectMapper()创建的，这样ObjectMapper会将Redis中的字符串反序列化为java.util.LinkedHashMap类型，导致后续Spring对其进行转换成报错。其实我们只要它返回Object类型就可以了。
以下修改了ObjectMapper一些参数，构建一个Jackson2JsonRedisSerializer对象，将其注入RedisCacheConfiguration即可。
代码语言：javascript复制private RedisCacheConfiguration getRedisCacheConfigurationWithTtl(Integer seconds) { // 设置 json 序列化 Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class); ObjectMapper om = new ObjectMapper(); om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY); om.configure(MapperFeature.USE_ANNOTATIONS, false); om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); om.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); // 此项必须配置，否则会报java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to XXX om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY); om.setSerializationInclusion(JsonInclude.Include.NON_NULL); jackson2JsonRedisSerializer.setObjectMapper(om); RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig(); redisCacheConfiguration = redisCacheConfiguration.serializeValuesWith( RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer)). // 设置过期时间 entryTtl(Duration.ofSeconds(seconds)); return redisCacheConfiguration;}
