log4j

I have a simple Spring Boot application that builds to a jar file. I have a log4j.xml file in src/main/resources/log4j.xml that looks like this (basic sample file from the log4j docs): <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd"> <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <appender name="stdout" class="org.apache.log4j.ConsoleAppender"> <layout class="org.apache.log4j.PatternLayout"> <!-- Pattern to output the caller's file name and line number --> <param name="ConversionPattern" value="%5p [%t] (%F:%L) - %m%n"/> </layout>

用Kepler eclipse自带的maven插件搞了一个maven项目，build的过程中出现如下红色信息： SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details. <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${org.slf4j-version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>${org.slf4j-version}</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.slf4j</groupId>

Is it possible to have log4j.xml loaded from a different dir than source root and how? (programmatically?) Meaning that it's somewhere in FS not just in classpath. Using DOMConfigurator you can specify the the XML file used to configure log4j. DOMConfigurator.configure("/path/to/log4j.xml"); For log4j.properties you can do the same thing with PropertyConfigurator . PropertyConfigurator.configure("/path/to/log4j.properties"); This might not be the best way, but you can specify the location of the file by setting the java property log4j.configuration=path/to/config/file. For example, you can

I am using log4cxx my project and i can able to log current thread id using [%t] marker, how to log process id in it or log4j?. I am using ConversionPattern & xml based configuration file. Thanks, skiphoppy Based on the above answers, I'm going to do this in log4j as follows: import java.lang.management.*; import org.apache.log4j.MDC; private String getPID() { RuntimeMXBean rt = ManagementFactory.getRuntimeMXBean(); return rt.getName(); } private void configLog4j() { // call this from somewhere before you start logging MDC.put("PID", getPID()); } Then in my log4j.properties: log4j.appender

添加各种jar包 /usr/local/hadoop/share/hadoop/.. 这几个文件夹下的jar包以及它们子目录lib下的所有jar包 将/usr/local/hadoop/etc/hadoop下的core-site.xml和hdfs-site.xml文件复制到新建工程的src下 同时新建日志文件log4j.properties log4j.rootLogger=INFO, stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n log4j.appender.logfile=org.apache.log4j.FileAppender log4j.appender.logfile.File=target/spring.log log4j.appender.logfile.layout=org.apache.log4j.PatternLayout log4j.appender.logfile.layout.ConversionPattern=%d %p [%c]

What's the advantage of log4j over set System.out and System.err to output to a log file? At a high level, the win from Log4j over manual logging is that you can decouple your logging code from what you actually want to log and where and how you want to log it. Details about logging verbosity/filtering, formatting, log location, and even log type (files, network, etc.) are handled declaratively using configuration and extensibly via custom appenders , rather you having to code that flexibility yourself. This is critically important because it's often hard for developers to predict how logging

Flume是一个完善、强大的日志采集工具，关于它的配置，在网上有很多现成的例子和资料，这里仅做简单说明不再详细赘述。 Flume包含Source、Channel、Sink三个最基本的概念： Source——日志来源，其中包括：Avro Source、Thrift Source、Exec Source、JMS Source、Spooling Directory Source、Kafka Source、NetCat Source、Sequence Generator Source、Syslog Source、HTTP Source、Stress Source、Legacy Source、Custom Source、Scribe Source以及Twitter 1% firehose Source。 Channel——日志管道，所有从Source过来的日志数据都会以队列的形式存放在里面，它包括：Memory Channel、JDBC Channel、Kafka Channel、File Channel、Spillable Memory Channel、Pseudo Transaction Channel、Custom Channel。 Sink——日志出口，日志将通过Sink向外发射，它包括：HDFS Sink、Hive Sink、Logger Sink、Avro Sink、Thrift

先占个坑 来源： https://www.cnblogs.com/suhaha/p/11794786.html

I need to append log4j content to a Swing component (JTextArea or similar). Is there a common way to do this? Instead of introducing an external library, I ended up editing the log4j.properties file to include the following: log4j.rootCategory=DEBUG, app log4j.appender.app=path.to.class.extending.WriterAppender Then I employed an observer pattern to post the data into my GUI's JTextArea. Thanks to Google, I've obviously discovered the Log4j-Swing-Appender . to make the JScrollPane wrapping the target component (e.g. JTextArea) automatically scroll down to show the latest log entries, consider