java jar 文件运行时未创建 Log4j 日志
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Log4j Log is not created when jar file run
提问by Pradeep Gamage
This is my Studentclass that used to test log4j.
这是我用来测试 log4j 的Student类。
public class Student{
private static final Logger logger = Logger.getLogger(Student.class.getName());
public Student() {
PropertyConfigurator.configure("log4j.properties");
}
public static void main(String args[]){
logger.log(Level.INFO, "My log4j Test");
}
}
This is my log4j.propertiesfile
这是我的log4j.properties文件
log4j.rootLogger=INFO,Appender1,Appender2
log4j.appender.Appender1=org.apache.log4j.ConsoleAppender
log4j.appender.Appender2=org.apache.log4j.RollingFileAppender
log4j.appender.Appender2.File=C:/Log4j/MyLogExample.log
log4j.appender.Appender1.layout=org.apache.log4j.PatternLayout`
log4j.appender.Appender1.Target=System.out`
log4j.appender.Appender1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n`
log4j.appender.Appender2.layout=org.apache.log4j.PatternLayout`
log4j.appender.Appender2.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n`
log4j.appender.Appender2.MaxFileSize=50KB`
log4j.appender.Appender2.MaxBackupIndex=10`
When I run this program using Eclipse MyLogExample.logfile gets created. But after I have created a jar file and run it using the command prompt, the log file is not created.
当我使用 Eclipse MyLogExample.log运行此程序时，会创建文件。但是在我创建了一个 jar 文件并使用命令提示符运行它之后，没有创建日志文件。
in console i can see this error.
在控制台中，我可以看到此错误。
log4j:ERROR Could not read configuration file [log4j.properties].
java.io.FileNotFoundException: log4j.properties (The system cannot find the file specified)
After I add the following code example, the log file is created even when the jar file run with command prompt.
添加以下代码示例后，即使 jar 文件在命令提示符下运行，也会创建日志文件。
PropertyConfigurator.configure("C:\eclipeworkspace\Log4jTest\log4j.properties");
How I can give relative path instead of exact path?
我如何给出相对路径而不是确切路径？
采纳答案by kjp
log4j.propertiesshould be in your classpath. Add it to the classpath when running from command line.
log4j.properties应该在你的类路径中。从命令行运行时将其添加到类路径中。
A better alternative is to specify the property file using
更好的选择是使用指定属性文件
-Dlog4j.configuration=relative path/log4j.properties
-Dlog4j.configuration=relative path/log4j.properties
from the command line.
In this case you can remove the line PropertyConfigurator.configure("log4j.properties");from your code - you don't need to do anything in the code to specify the property file.
从命令行。在这种情况下，您可以PropertyConfigurator.configure("log4j.properties");从代码中删除该行- 您无需在代码中执行任何操作来指定属性文件。
回答by Rudy
Use this :
用这个 ：
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
URL url = classLoader.getResource("log4j.properties");
File file = new File(url.toURI());
回答by akshay
add this plugin if using maven to make your jar runnable wilth all depenencies
如果使用 Maven 使您的 jar 可运行并具有所有依赖项，请添加此插件
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<mainClass>cnnc.bcyr.nvnvn.nch.MainclassName</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
