blocks|key|1102477|text|记录未捕获的RuntimeExceptions+(或任何未捕获的Throwable)的一种方法是创建一个实现Thread.UncaughtExceptionHandler的类。该类的uncaughtException()方法将简单地将异常详细信息写入日志。只要未捕获的RuntimeException通过添加以下行终止线程，就可以使JVM调用此异常处理程序。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1102478|Thread.setDefaultUncaughtExceptionHandler(new+MyExceptionHandler());|code-block|syntax|javascript|1102479|添加到您的代码。|1102480|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.UncaughtExceptionHandler.html^0|2J|J|1I|V|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|11|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

One way to log uncaught RuntimeExceptions (or any uncaught Throwables for that matter) is to create a class that implements <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.UncaughtExceptionHandler.html" rel="noreferrer">Thread.UncaughtExceptionHandler</a>. This class's <code>uncaughtException()</code> method would simply write the exception details to the log. You can make the JVM call this exception handler whenever an uncaught RuntimeException terminates a thread by adding the line

<pre><code>Thread.setDefaultUncaughtExceptionHandler(new MyExceptionHandler());
</code></pre>

to your code.

blocks|key|1317497|text|我不确定这是否是您想要的，但是有一个异常处理程序可以终止线程。它是未被线程的目标显式捕获的任何异常的处理程序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317498|默认的“未捕获异常处理程序”只是在Throwable上调用printStackTrace()，将堆栈跟踪打印到System.err。但是，您可以使用您自己的UncaughtExceptionHandler来replace它，它将异常记录到log4j中：|offset|length|style|CODE|1317499|class+Log4jBackstop+implements+Thread.UncaughtExceptionHandler+{

++private+static+Logger+log+=+Logger.getLogger(Log4jBackstop.class);

++public+void+uncaughtException(Thread+t,+Throwable+ex)+{
++++log.error("Uncaught+exception+in+thread:+"+%2B+t.getName(),+ex);
++}

}|code-block|syntax|javascript|1317500|如果您正在使用向其传递Runnable对象的executor框架，则其线程可能具有自己的catch块，以防止异常到达未捕获的异常处理程序。如果您想在那里捕获Runtime异常，一种方法是将每个任务包装在日志包装器中，如下所示：|1317501|class+Log4jWrapper+{

++private+final+Logger+log;

++private+final+Runnable+target;

++Log4jWrapper(Logger+log,+Runnable+target)+{+
++++this.log+=+Objects.requireNonNull(log);
++++this.target+=+Objects.requireNonNull(target);+
++}

++public+void+run()+{
++++try+{
++++++target.run();
++++}+catch(RuntimeException+ex)+{
++++++log.error("Uncaught+exception.",+ex);
++++++throw+ex;
++++}
++}

}

...

Runnable+realTask+=+...;
executor.submit(new+Log4jWrapper(Logger.getLogger(Whatever.class),+realTask));|1317502|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/javase/6/docs/api/java/lang/Thread.UncaughtExceptionHandler.html|1|http://java.sun.com/javase/6/docs/api/java/lang/Thread.html#setDefaultUncaughtExceptionHandler%2528java.lang.Thread.UncaughtExceptionHandler%2529^0|0|H|9|T|H|1J|A|26|O|26|O|0|2V|7|1|0|0|B|8|18|5|26|7|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@$D|12|E|13|F|G]|$D|14|E|15|F|G]|$D|16|E|17|F|G]|$D|18|E|19|F|G]]|9|@$D|1A|E|1B|1|1C]|$D|1D|E|1E|1|1F]]|A|$]]|$1|H|3|I|5|J|7|1G|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1H|8|@$D|1I|E|1J|F|G]|$D|1K|E|1L|F|G]|$D|1M|E|1N|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|1O|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]|Y|$5|T|U|V|A|$W|Z]]]]

I'm not sure if this is what you are looking for, but there is a handler for exceptions that terminate threads. It is a handler for any exception that is not caught explicitly by the target of the thread.

The default "uncaught exception handler" simply calls <code>printStackTrace()</code> on the <code>Throwable</code> to print the stack trace to <code>System.err</code>. However, you could <a href="http://java.sun.com/javase/6/docs/api/java/lang/Thread.html#setDefaultUncaughtExceptionHandler%28java.lang.Thread.UncaughtExceptionHandler%29" rel="noreferrer">replace</a> this with your own <a href="http://java.sun.com/javase/6/docs/api/java/lang/Thread.UncaughtExceptionHandler.html" rel="noreferrer"><code>UncaughtExceptionHandler</code></a> that logs the exception to log4j instead:

<pre><code>class Log4jBackstop implements Thread.UncaughtExceptionHandler {

 private static Logger log = Logger.getLogger(Log4jBackstop.class);

 public void uncaughtException(Thread t, Throwable ex) {
 log.error("Uncaught exception in thread: " + t.getName(), ex);
 }

}
</code></pre>

If you are using an executor framework to which you pass a <code>Runnable</code> object, its threads probably have their own <code>catch</code> block that prevent exceptions from reaching the uncaught exception handler. If you want to catch <code>Runtime</code> exceptions there, one way to do it is to wrap each task in a logging wrapper, like this:

<pre><code>class Log4jWrapper {

 private final Logger log;

 private final Runnable target;

 Log4jWrapper(Logger log, Runnable target) { 
 this.log = Objects.requireNonNull(log);
 this.target = Objects.requireNonNull(target); 
 }

 public void run() {
 try {
 target.run();
 } catch(RuntimeException ex) {
 log.error("Uncaught exception.", ex);
 throw ex;
 }
 }

}

...

Runnable realTask = ...;
executor.submit(new Log4jWrapper(Logger.getLogger(Whatever.class), realTask));
</code></pre>

I am currently building an application using Tomcat, Spring and JAVA. I am using <code>Log4J</code> as my logging library. I currently am logging everything to a text file. One of the issues I'm having is that <code>RuntimeExceptions</code> are not being logged to any files. I was wondering if there is a way to log all <code>RuntimeExceptions</code> that maybe thrown to my application log file. If not is it possible to have it log to another log file? Is there a standard way to do this? If so is there a standard way to do this when running your application within Tomcat?

Thank you in advance for your help!

Log runtime Exceptions in Java using log4j

日志文件

我目前正在使用Tomcat、Spring和JAVA构建一个应用程序。我使用Log4J作为我的日志库。我目前正在将所有内容记录到一个文本文件中。我遇到的一个问题是RuntimeExceptions没有被记录到任何文件中。我想知道是否有一种方法可以将可能抛出到我的应用程序日志文件中的所有RuntimeExceptions记...

问使用log4j在Java中记录运行时异常
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