如何解决此“ClassNotFoundException”错误

Question

你好，我收到了这个错误

错误：无法找到或加载主类 Log4jEx.BasicConfiguratorEx 引起：java.lang.ClassNotFoundException: Log4jEx.BasicConfiguratorEx

这是我的程序

package Log4jEx;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;

public class BasicConfiguratorEx {

    static Logger logger = Logger.getLogger(BasicConfiguratorEx.class); 
    //Creating object for Logger without NEW//

    public static void main(String[] args) {            
        BasicConfigurator.configure();
        logger.debug("This is a debug");
        logger.info("This is a info");
        logger.warn("This is a warn");
        logger.fatal("This is a fatal message");    
    }    
}

Answer 1

log4j 1.x

BasicConfigurator 是 log4j 1.2 类，不能用于配置 Log4j 2。

Log4j 1.x 的生命周期已经结束

如果你想在你的项目中使用 BasicConfigurator。

1. 从此website下载log4j 1.2 jar。
2. 将 log4j-1.2.17 作为外部 jar 文件添加到您的项目构建路径中。

log4j 2.x

不需要 BasicConfigurator 类。

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class HelloWorld {
    private static final Logger logger = LogManager.getLogger("HelloWorld");
    public static void main(String[] args) {
        logger.debug("This is debug message");
        logger.info("This is info message");
        logger.warn("This is warn message");
        logger.fatal("This is fatal message");
        logger.error("This is error message");
        System.out.println("Executed successfully....");

    }
}

output:
This is debug message
This is info message
This is warn message
This is fatal message
This is error message
Logic executed successfully....

在 src/main/resources 下添加 log4j2.properties 文件

name=PropertiesConfig

rootLogger.level=debug
rootLogger.appenderRefs=stdout
rootLogger.appenderRef.stdout.ref=StandardOutput

appenders=console

#log messages to terminal
appender.console.type=Console
appender.console.name=StandardOutput

在 pom.xml 中添加以下依赖项

<dependency>
   <groupId>org.apache.logging.log4j</groupId>
   <artifactId>log4j-api</artifactId>
   <version>2.13.1</version>
</dependency>
<dependency>
   <groupId>org.apache.logging.log4j</groupId>
   <artifactId>log4j-core</artifactId>
   <version>2.13.1</version>
</dependency>

我希望这会有所帮助。