Java HttpServlet引发的ServletException被记录为';严重';由Tomcat执行,尽管以推荐的方式处理 问题描述
当我的HttpServlet抛出ServletException时,Tomcat正在记录一条严重的消息,包括stacktrace,尽管它被正确地重新定向到web.xml中的另一个HttpServlet Tomcat使用stacktrace记录以下消息:Java HttpServlet引发的ServletException被记录为';严重';由Tomcat执行,尽管以推荐的方式处理 问题描述,java,tomcat,servlets,exception-handling,servletexception,Java,Tomcat,Servlets,Exception Handling,Servletexception,当我的HttpServlet抛出ServletException时,Tomcat正在记录一条严重的消息,包括stacktrace,尽管它被正确地重新定向到web.xml中的另一个HttpServlet Tomcat使用stacktrace记录以下消息: 21-Mar-2015 15:24:57.521 SEVERE [http-nio-8080-exec-28] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.servic
21-Mar-2015 15:24:57.521 SEVERE [http-nio-8080-exec-28] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [MyHttpServlet] in context with path [/HttpServletExceptionHandler] threw exception [CustomException] with root cause CustomException
at MyHttpServlet.doGet(MyHttpServlet.java:20)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
我做了什么?
首先,MyHttpServlet在其doGet()方法中抛出一个封装CustomException(Exception的子类)的ServletException:
然后,抛出的CustomException被重新定向到MyServletExceptionHandler(映射到位置“/MyServletExceptionHandler”)。此重新定向在web.xml中以以下方式定义:
<error-page>
<exception-type>CustomException</exception-type>
<location>/MyServletExceptionHandler</location>
</error-page>
这会导致预期的“MyServletExceptionHandler捕获Throwable:CustomException”打印,因此这确实有效,但Tomcat也会记录上面提到的严重消息,包括stacktrace。这会打乱我的日志记录
我为什么要这样?
根据JavaBeat的观点,上述方法是处理servlet中异常处理的正确方法。问题29状态(扰流板警报:粗体是正确答案):
如果出现从java.lang.exception扩展而来的业务异常,以下哪种方式是向客户端发送错误页面的合理方式
- 抛出RuntimeExceptions而不是ServletExceptions会导致相同的严重日志
- 该问题的工作示例通过提供
public abstract class MyServletBase extends HttpServlet {
@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp) {
try {
doGetInternal(req, resp);
} catch (RuntimeException e) {
handleError(e, req, resp);
}
}
protected void handleError(RuntimeException e, HttpServletRequest req, HttpServletResponse resp) {
// Error handling logic goes here
}
protected void doGetInternal(HttpServletRequest req, HttpServletResponse resp);
}
然后是实际的servlet:
public class MyServlet extends MyServletBase {
@Override
protected void doGetInternal(HttpServletRequest req, HttpServlet resp) {
// Actual servlet logic here
}
}
这是我脑海中的一个粗略的草图,没有提及Javadoc,因此可能没有完美的方法签名,但希望您能理解
它还有一个优点,即如果您需要向派生servlet添加额外的错误处理逻辑,并且不想出于任何原因更改基本servlet,那么您只需重写
handleError()
方法,这在使用Tomcat的异常处理机制时不是很容易做到的。@Klikodid你解决了你的问题吗?不,谢谢你的帮助,虽然问题是在你的最后一次编辑中出现的,edit:BUMP
这是不合适的。@Kliko-当我从整体上看问题时,它有点大很难理解。它漫无目的地讲,没有真正的结构。我试着阅读它,但失去了所有的兴趣。我几乎看不出问题陈述。你也没有提供导致异常的代码(相反,它漫无目的地讲其他事情,比如关于事情应该如何工作的文档和博客帖子)你可能会考虑最后一次编辑,并把它与需要帮助的必要信息联系起来。现在它已经结束了,我倾向于同意——不清楚你在问什么,需要最少的例子。
public abstract class MyServletBase extends HttpServlet {
@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp) {
try {
doGetInternal(req, resp);
} catch (RuntimeException e) {
handleError(e, req, resp);
}
}
protected void handleError(RuntimeException e, HttpServletRequest req, HttpServletResponse resp) {
// Error handling logic goes here
}
protected void doGetInternal(HttpServletRequest req, HttpServletResponse resp);
}
public class MyServlet extends MyServletBase {
@Override
protected void doGetInternal(HttpServletRequest req, HttpServlet resp) {
// Actual servlet logic here
}
}