当我运行以下简单的 log4J 示例时,出现错误:
import org.apache.logging.log4j.core.*;
import java.io.*;
import java.sql.SQLException;
import java.util.*;
public class log4jExample{
/* Get actual class name to be printed on */
static Logger log = Logger.getLogger(
log4jExample.class.getName());
public static void main(String[] args)
throws IOException,SQLException{
log.debug("Hello this is an debug message");
log.info("Hello this is an info message");
}
}
错误如下:
Error: package org.apache.logging.log4j.core does not exist
Error: cannot find symbol
symbol: class Logger
location: class log4jExample
File: C:\Users\adel\Desktop\various_topics\JavaProjects\log4jExample.java [line: 10]
Error: cannot find symbol
symbol: variable Logger
location: class log4jExample
所以我相信我正确地将 log4J 添加到类路径中,如下所示:
我提取了jar
file log4j-core-2.0-beta4.jar
从 apache 目录如下:
我不确定发生了什么 - 导入语句如何工作?即网上的例子告诉我:
import org.apache.log4j.Logger;
但如果我的目录结构是这样的怎么办:
\apache-log4j-2.0-beta4-bin\org\apache\logging\log4j\core\Logger.java
我是否不得不说:
import org.apache.logging.log4j.core.Logger;
instead?