log4j

问题 How do you configure log4j.properties to have exactly one logfile per run of an app. I've read that you should use a timestamp in the filename but that will create many files per run as time goes by. I tried DailyRollingFileAppender and RollingFileAppender but can't find a way to configure exctly one log per run. The log should not be broken into multiple logs and it shouldn't be truncated and files of old runs should be preserved. Each class has a static org.slf4j.Logger for it's own class

问题 I'm trying to create a log of hibernate statements. I perform my sql statements using JPA where Hibernate 2.0 is the persistence provider (my application server is JBoss AS 6.0). I call my CRUD methods using the EntityManager interface provided by EJB 3.0. I read many posts about enabling hinernate logging but actually i can't see any log :-( I create a log4j.properties file and I put it in the root folder of my Netbeans project. I put also log4j library in the classpath of the project. My

问题 I used tomcat and simply override default logging system. How to enable logging with logback on wildfly in my spring app? My Logback.xml owrking on tomcat <?xml version="1.0" encoding="UTF-8"?> <configuration> <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> <filter class="ch.qos.logback.classic.filter.LevelFilter"> <level>ERROR</level> <onMatch>ACCEPT</onMatch> <onMismatch>DENY</onMismatch> </filter> <encoder> <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n<

问题 I want to log only the first few lines of Exceptions in my program. I know, I can do something like this to print only the first 5 lines of a stacktrace: Throwable e = ...; StackTraceElement[] stack = e.getStackTrace(); int maxLines = (stack.length > 4) ? 5 : stack.length; for (int n = 0; n < maxLines; n++) { System.err.println(stack[n].toString()); } But I would rather use log4j (or slf4j over log4j to be more precise) for logging. Is there a way to tell log4j that it should only print the

问题 In log4j, when using a FileAppender with BufferedIO=true and BufferSize=xxx properties (i.e. buffering is enabled), I want to be able to flush the log during normal shutdown procedure. Any ideas on how to do this? 回答1: public static void flushAllLogs() { try { Set<FileAppender> flushedFileAppenders = new HashSet<FileAppender>(); Enumeration currentLoggers = LogManager.getLoggerRepository().getCurrentLoggers(); while(currentLoggers.hasMoreElements()) { Object nextLogger = currentLoggers

问题 I've been using log4j for quite a while now and I usually use this at the top of the log4j.xml (probably just like many others and according to Google this is the way to do it): <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd"> Obviously this is working, however Eclipse doesn't provide its context-sensitive help for writing the XML and all. Furthermore, it always shows a warning that it doesn't find the log4j.dtd . Now I'm curious how to fix this. I tried a few things and these work: <

问题 I've been using log4j for quite a while now and I usually use this at the top of the log4j.xml (probably just like many others and according to Google this is the way to do it): <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd"> Obviously this is working, however Eclipse doesn't provide its context-sensitive help for writing the XML and all. Furthermore, it always shows a warning that it doesn't find the log4j.dtd . Now I'm curious how to fix this. I tried a few things and these work: <

问题 Looking at the last JUnit test case I wrote, I called log4j's BasicConfigurator.configure() method inside the class constructor. That worked fine for running just that single class from Eclipse's "run as JUnit test case" command. But I realize it's incorrect: I'm pretty sure our main test suite runs all of these classes from one process, and therefore log4j configuration should be happening higher up somewhere. But I still need to run a test case by itself some times, in which case I want

问题 Say you catch an exception and get the following on the standard output (like, say, the console) if you do a e.printStackTrace() : java.io.FileNotFoundException: so.txt at java.io.FileInputStream.<init>(FileInputStream.java) at ExTest.readMyFile(ExTest.java:19) at ExTest.main(ExTest.java:7) Now I want to send this instead to a logger like, say, log4j to get the following: 31947 [AWT-EventQueue-0] ERROR Java.io.FileNotFoundException: so.txt 32204 [AWT-EventQueue-0] ERROR at java.io

问题 Since in log4j javadoc is WARNING: This version of JDBCAppender is very likely to be completely replaced in the future. Moreoever, it does not log exceptions. What should I do to log to a database? 回答1: If you are looking for a database appender which not only works, but also supports connection pooling, is maintained and properly documented, than consider logback's DBAppender. Ironically enough, the warning in the javadocs about removing JDBCAppender in future versions of log4j was written