Question

我们使用REST端点提供CMS（Hippo）内容，我注意到间歇性发生的奇怪行为：

一次又一次，在一段不活动或服务器重启后第一次调用端点（例如http://site.name/api/articles/）时，会抛出以下异常。如果页面第二次刷新，则一切正常。

Throwable thrown during doFilter on request with URI: /site/fr-ca/api/articles/ and Query: nullResponse already committed after doing buildPage but before writing response from PageInfo.
[INFO] [talledLocalContainer] net.sf.ehcache.constructs.web.AlreadyCommittedException: Response already committed after doing buildPage but before writing response from PageInfo.
[INFO] [talledLocalContainer]   at net.sf.ehcache.constructs.web.filter.CachingFilter.doFilter(CachingFilter.java:220)
[INFO] [talledLocalContainer]   at net.sf.ehcache.constructs.web.filter.Filter.doFilter(Filter.java:86)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer]   at org.hippoecm.hst.container.XSSUrlFilter.doFilter(XSSUrlFilter.java:52)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer]   at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
[INFO] [talledLocalContainer]   at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardContextValve.__invoke(StandardContextValve.java:106)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java)
[INFO] [talledLocalContainer]   at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardHostValve.__invoke(StandardHostValve.java:142)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java)
[INFO] [talledLocalContainer]   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
[INFO] [talledLocalContainer]   at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
[INFO] [talledLocalContainer]   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
[INFO] [talledLocalContainer]   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
[INFO] [talledLocalContainer]   at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
[INFO] [talledLocalContainer]   at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
[INFO] [talledLocalContainer]   at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1521)
[INFO] [talledLocalContainer]   at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1478)
[INFO] [talledLocalContainer]   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[INFO] [talledLocalContainer]   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[INFO] [talledLocalContainer]   at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
[INFO] [talledLocalContainer]   at java.lang.Thread.run(Thread.java:745)

下面给出了罪魁祸首代码：

protected void doFilter(final HttpServletRequest request,
        final HttpServletResponse response, final FilterChain chain)
        throws AlreadyGzippedException, AlreadyCommittedException,
        FilterNonReentrantException, LockTimeoutException, Exception {
    if (response.isCommitted()) {
        throw new AlreadyCommittedException(
                "Response already committed before doing buildPage.");
    }
    logRequestHeaders(request);
    PageInfo pageInfo = buildPageInfo(request, response, chain);

    if (pageInfo.isOk()) {
        if (response.isCommitted()) {
            throw new AlreadyCommittedException(
                    "Response already committed after doing buildPage"
                            + " but before writing response from PageInfo.");
        }
        writeResponse(request, response, pageInfo);
    }
}

第220行是在AlreadyCommittedException()

内投掷if(response.isCommitted()) {}的行

这让我觉得服务器认为此时响应已经提交。我检查了我的代码，我可以确认我没有做任何＆＃34;中间＆＃34;提交或写入servlet的输出流。

但是最烦人的是，它只发生在第一页调用上，如果我刷新页面问题就消失了。

其他细节：我们有一个缓存过滤器来缓存页面并调用CacheFilter：

public class WaPageCache extends SimpleCachingHeadersPageCachingFilter {

    @Override
    protected String calculateKey(HttpServletRequest httpRequest) {
        String simpleKey = super.calculateKey(httpRequest);
        final String requestURI = httpRequest.getRequestURI();
        final String key = requestURI.contains("/binaries/content") ? simpleKey : simpleKey + httpRequest.getHeader("Cookie");
        return key;
    }

    @Override
    protected CacheManager getCacheManager() {
        ClassLoader standardClassloader = Thread.currentThread().getContextClassLoader();
        URL url = null;
        if (standardClassloader != null) {
            url = standardClassloader.getResource("ehcache-web-caching.xml");
        }
        return CacheManager.create(url);
    }
}

是否还有其他人遇到类似问题，解决方案的可能原因/解决方案/提示是什么？

Answer 1

我找到了一个修复：在我的webapp中，我有几个过滤器，诀窍是将缓存过滤器放在所有其他过滤器之后（在我的Hippo案例中，特别是在HstFilter之后）。好吧，我有另一个设置响应头的过滤器，并且可以使用缓存过滤器。这是我更新的web.xml的一个片段：

>>> with open('commedia.pfc', 'rb') as f:
>>>    print(len(f.read()))
461491

AlreadyCommittedException：在执行buildPage之后但在从PageInfo（HippoCMS）写入响应之前已经提交了响应

1 个答案: