遇到问题运行 Log4J HelloWorld 示例，出现 "package does not exist" 错误

Question

我在处理 Log4J 示例时遇到问题运行。我不确定这是配置问题还是编码问题。这是我的示例代码：

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

public class HelloWorldLog4J {

    private static final Logger logger = LogManager.getLogger("HelloWorld");


    public static void main(String[] args) {

        System.out.println("pre_loggerDOTinfo");
        System.out.println();
        //logger.setLevel(Level.FATAL);   //used to be.. 

        logger.info("Hello, this is an INFO message");
        logger.warn("Hello, this is an WARN  message");
        logger.fatal("Hello, this is an FATAL  message");
        logger.fatal("Hello, this is an FATAL  message ALSO, #2");
        logger.debug("Hello, this is an FATAL  message");


        logger.info("Hello, this is an INFO message");
        System.out.println();
        System.out.println("post_loggerDOTinfo");

    }



}

但是当我运行这个时，我得到以下错误：

C:\Users\Adel\JavaCoding>javac HelloWorldLog4J.java
HelloWorldLog4J.java:1: error: package org.apache.logging.log4j does not exist
import org.apache.logging.log4j.LogManager;
                               ^
HelloWorldLog4J.java:2: error: package org.apache.logging.log4j does not exist
import org.apache.logging.log4j.Logger;
                               ^
HelloWorldLog4J.java:3: error: package org.apache.logging.log4j does not exist
import org.apache.logging.log4j.Level;
                               ^
HelloWorldLog4J.java:7: error: cannot find symbol
    private static final Logger logger = LogManager.getLogger("HelloWorld");
                         ^
  symbol:   class Logger
  location: class HelloWorldLog4J
HelloWorldLog4J.java:7: error: cannot find symbol
    private static final Logger logger = LogManager.getLogger("HelloWorld");
                                         ^
  symbol:   variable LogManager
  location: class HelloWorldLog4J

我相信我的类路径设置正确，我设置了 3 个变量：

LOG4J_HOME - %log4j-api%;%log4j-core%

log4j-api - C:\apache_log4j_beta5\apache-log4j-2.0-beta5-bin\log4j-api-2.0-beta5-sources.jar

log4j-core - C:\apache_log4j_beta5\apache-log4j-2.0-beta5-bin\log4j-core-2.0-beta5-sources.jar

这是我的目录结构（full-image link）：

我在想是不是 log4j 的版本不对？我的版本是这个： apache-log4j-2.0-beta5-bin 和 I downloaded it from this link

感谢任何提示，谢谢

Answer 1

您需要在运行 javac 之前将 log4j jar 添加到您的 CLASSPATH 变量中。或者，您可以使用 -cp 选项在此处指定路径。

javac -cp <path> HelloWorldLog4J.java

其中路径是 log4j jar 的绝对路径，每个路径由冒号字符 (:) 分隔。使用 cp 选项时还应该包括当前目录，这由句点字符 (.)

表示

编辑：您想要引用包含 log4j 的 class 文件的 jar 文件，而不是 java 文件，例如log4j-core-2.0-beta5.jar，不是 log4j-core-2.0-beta5-sources.jar.

遇到问题 运行 Log4J HelloWorld 示例，出现 "package does not exist" 错误

Having trouble running Log4J HelloWorld example, getting the "package does not exist" error

java

logging

log4j

遇到问题运行 Log4J HelloWorld 示例，出现 "package does not exist" 错误