在Java程序中初始化log4j属性文件时出现java.lang.Class:ERROR [英] java.lang.Class:ERROR while initializing log4j properties file in java program

问题描述

我正在尝试使用log4j运行独立的Java程序，但在调试时收到以下消息(控制台上没有与log4j相关的日志):

I am trying to run a standalone java program using log4j, but receiving below while debugging (with no log4j related logs on console):

log= {Logger@1343} "java.lang.Class:ERROR in 18b4aac2"

有人可以在这里提出什么问题吗?

Can someone please suggest what is wrong here?

代码如下:

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.Logger;
import java.io.IOException;
import java.sql.SQLException;

public class log4jExample {

static org.apache.logging.log4j.Logger log = LogManager.getLogger(log4jExample.class.getClass());

public static void main(String[] args)throws IOException,SQLException {
    System.out.println("in main...");

    log.debug("Hello this is a debug message");
    System.out.println("in main...2..");
    log.info("Hello this is an info message");
}

}

log4j.properties文件如下所示，该文件保存在src/main/resources中.

And the log4j.properties file is as below which is kept at src/main/resources.

log4j.rootLogger=DEBUG, stdout, file
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=C:\\test\\log4j-example.log
log4j.appender.file.MaxFileSize=1MB
log4j.appender.file.MaxBackupIndex=2
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

我正在通过VM选项运行Java程序

I am running my java program with VM option

-Dlog4j.configurationFile=C:\MyFirstProject\src\main\resources\log4j.properties

推荐答案

在我看来，您好像混用了log4j版本.您使用的配置文件使用log4j 1.x格式.您必须将其转换为log4j 2.x格式.我试过你的例子，它的工作原理.请参阅下面的详细信息.

It seems to me like you have mixed up log4j versions. The configuration file you use is using log4j 1.x format. You have to convert it to log4j 2.x format. I tried your example and it works. See details below.

pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.bft.</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.7</version>
        </dependency>
    </dependencies>
</project>

重构代码

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

public class log4jExample {

    static final Logger logger = LogManager.getLogger(log4jExample.class);

    public static void main(String[] args) {
        System.out.println("in main...");

        logger.info("Hello this is a debug message");
        System.out.println("in main...2..");
        logger.info("Hello this is an info message");
    }
}

log4j.properties文件(格式为log4j2.x)

log4j.properties file (in log4j2.x format)

status = error
dest = err
name = PropertiesConfig

filter.threshold.type = ThresholdFilter
filter.threshold.level = debug

appender.console.type = Console
appender.console.name = STDOUT
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %m%n

rootLogger.level = info
rootLogger.appenderRef.stdout.ref = STDOUT

输出:

in main...
Hello this is a debug message
in main...2..
Hello this is an info message

Process finished with exit code 0

请参阅log4j 文档.

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