Java集合sort排序报错UnsupportedOperationException处理
文章目录
-
- 报错场景
- 排查解决
- UnmodifiableList类介绍
报错场景
- 我们使用的是PostgreSQL数据库，存储业务数据，业务代码使用的是Spring JPA
- 我们做的是智慧交通信控平台，有个功能是查询展示区域的交通态势，需要按照不同维度排序展示
- 区域态势指标计算，15分钟一次，每次计算存储所有区域指标。我们的实时态势展示，每次展示当前最新结果
- 业务要求，要按照区域交通流量、拥堵指数、拥堵里程分别倒序展示，写在了一个接口里，先查询后排序
- 我们使用的默认自增的主键策略，故获取最新一次区域态势结果，可以使用id倒序，按照区域数量获取
- 查询的业务逻辑比较简单，代码很快就写完了，使用JPA查询语句，构造查询和排序条件。得到查询结果list后，再根据业务需要，按照不同的字段排序
- 但在部署测试环境后发现，排序代码执行报错，报错
null Not Implemented - 具体业务代码如下
/**
* 获取所有区域实时态势
* @param targetIndex 排序字段
* @return
*/
public List<SituationAnalysisRegion> getCurrentRegionSituationList(String targetIndex) {
// 获取所有子区
List<SubRegion> allSubRegions = getAllSubRegion();
Map<Integer, SubRegion> idSubRegionMap = new HashMap<>();
allSubRegions.forEach(e -> idSubRegionMap.put(e.getId().intValue(), e));
// 获取所有子区态势排名倒序
Specification<SituationAnalysisRegion> specification = (root, query, cb)->{
List<Predicate> predicates = new ArrayList<>();
predicates.add(cb.greaterThan(root.get("timeStamp").as(Instant.class), LocalDateTime.now().plusMinutes(-15).plusSeconds(-30).atZone(ZoneId.systemDefault()).toInstant()));
Predicate[] pre = new Predicate[predicates.size()];
pre = predicates.toArray(pre);
return query.where(pre).getRestriction();
};
Sort orders = Sort.by("id").descending();
Pageable pageable = PageRequest.of(0, allSubRegions.size(), orders);
List<SituationAnalysisRegion> situationAnalysisRegions = analysisRegionRepository.findAll(specification, pageable).getContent();
// 排序要求
if (null == targetIndex || StringUtils.isEmpty(targetIndex)) {
situationAnalysisRegions.sort((o1, o2) -> (int)(o2.getCongestionMileage() - o1.getCongestionMileage()));
} else if (targetIndex.equals("trafficFlow")) {
situationAnalysisRegions.sort((o1, o2) -> o2.getTrafficFlow() - o1.getTrafficFlow());
} else if (targetIndex.equals("congestionIndex")) {
situationAnalysisRegions.sort((o1, o2) -> (int)(o2.getCongestionIndex() - o1.getCongestionIndex()));
} else {
situationAnalysisRegions.sort((o1, o2) -> (int)(o2.getCongestionMileage() - o1.getCongestionMileage()));
}
return situationAnalysisRegions;
}
- 具体报错日志如下：
2023-08-29 16:12:56.168 ERROR 12860 --- [ XNIO-1 task-1] o.z.problem.spring.common.AdviceTraits : Not Implemented
java.lang.UnsupportedOperationException: null
at java.base/java.util.Collections$UnmodifiableList.sort(Collections.java:1332)
at com.newatc.api.situationanalysis.service.SituationAnalysisRegionExtentService.getCurrentRegionSituationList(SituationAnalysisRegionExtentService.java:88)
at com.newatc.api.situationanalysis.service.SituationAnalysisRegionExtentService.getRegionSituationList(SituationAnalysisRegionExtentService.java:104)
at com.newatc.api.rest.SituationAnalysisController.getRegionSituationList(SituationAnalysisController.java:112)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1070)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
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:497)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:584)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:91)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at com.newatc.api.redis.RequestFilter.doFilter(RequestFilter.java:58)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:327)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:122)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:126)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:81)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.oauth2.client.web.OAuth2AuthorizationCodeGrantFilter.doFilterInternal(OAuth2AuthorizationCodeGrantFilter.java:168)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:109)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.oauth2.server.resource.web.BearerTokenAuthenticationFilter.doFilterInternal(BearerTokenAuthenticationFilter.java:125)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.oauth2.client.web.OAuth2AuthorizationRequestRedirectFilter.doFilterInternal(OAuth2AuthorizationRequestRedirectFilter.java:178)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:112)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:82)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.session.DisableEncodeUrlFilter.doFilterInternal(DisableEncodeUrlFilter.java:42)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:211)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:117)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.SessionRestoringHandler.handleRequest(SessionRestoringHandler.java:119)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:275)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:79)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:134)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:131)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:255)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:79)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:100)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1449)
at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282)
at java.base/java.lang.Thread.run(Thread.java:834)
2023-08-29 16:12:56.227 WARN 12860 --- [ XNIO-1 task-1] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [java.lang.UnsupportedOperationException]
排查解决
-
日志核心打印：
Not Implemented、java.lang.UnsupportedOperationException: null、at java.base/java.util.Collections$UnmodifiableList.sort(Collections.java:1332) -
一开始看着报错
null，以为是空指针异常，想着是不是没查询到数据，或者排序字段的值有null值 -
查看了数据库数据，发现没问题，只好本地debug排查
-
加了断点，进行debug，确认返回结果list有值，且排序字段也都有值，继续执行，还是这个报错
-
想着要进行更细粒度的debug，于是按着 F5 继续调试，结果发现，也是直接一步走进报错，在这一行（Collections.sort）
-
一下子没法排查了，这个报错之前也没注意过，于是继续去网上搜索相应报错，还真找到了
-
还是要回到报错日志，核心是这一句：
at java.base/java.util.Collections$UnmodifiableList.sort(Collections.java:1332) -
在执行
Collections.sort()方法时，发现传入的集合list，是一个不可修改的UnmodifiableList.，不能直接拿来排序 -
但是可以通过新建一个list，来解决这个问题
List<SituationAnalysisRegion> situationAnalysisRegions = analysisRegionRepository.findAll(specification, pageable).getContent();
// 重新赋值，排除 UnmodifiableList 报错
List<SituationAnalysisRegion> result = new ArrayList<>(situationAnalysisRegions);
// 排序要求
if (null == targetIndex || StringUtils.isEmpty(targetIndex)) {
result.sort((o1, o2) -> (int)(o2.getCongestionMileage() - o1.getCongestionMileage()));
} else if (targetIndex.equals("trafficFlow")) {
result.sort((o1, o2) -> o2.getTrafficFlow() - o1.getTrafficFlow());
} else if (targetIndex.equals("congestionIndex")) {
result.sort((o1, o2) -> (int)(o2.getCongestionIndex() - o1.getCongestionIndex()));
} else {
result.sort((o1, o2) -> (int)(o2.getCongestionMileage() - o1.getCongestionMileage()));
}
return result;
- 现在问题很明确了，JPA的查询代码，返回的list，是个不可修改的list。在网上查询该问题时，发现其他的一些类似查询，也可能返回一个不可修改的list，如 MongoDB的Java查询语句
- 以后如果看到
Collections$UnmodifiableList.sort报错，就要考虑到这种情况，都可以类似处理
UnmodifiableList类介绍
- UnmodifiableList类是Collections的内部类
- Java的Collections框架提供了UnmodifiableList类作为不可变列表的一种实现
- UnmodifiableList实现了List接口，但是在其基础上增加了一些限制，例如不允许修改列表中的元素、不允许添加新元素以及不允许删除已有元素。因此，可以使用UnmodifiableList来保护某些关键数据，防止其他程序修改它们
- 使用方式非常简单，通过Collections.unmodifiableList(List list)方法可以将一个可变的列表转换为一个不可变的列表，例如：
List mutableList = new ArrayList<>();
mutableList.add("apple");
mutableList.add("banana");
mutableList.add("orange");
List immutableList = Collections.unmodifiableList(mutableList);
- 这样，immutableList就成为了一个不可变的列表，任何尝试修改、添加或删除其中的元素的操作都会抛出UnsupportedOperationException异常。