在Idea中，配置log4j.xml出现“http //jakarta.apache.org/log4j/ uri is not registered”的错误信息，解决步骤如下：

• 1、原始的log4j.xml配置文件：
  

<?xml version="1.0" encoding="GB2312" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
    <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
        <param name="Encoding" value="UTF-8"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{HH:mm:ss,SS} %-5p (%C{1}:%M) - %m%n"/>
        </layout>
    </appender>
    <logger name="java.sql">
        <level value="debug"/>
    </logger>
    <logger name="org.apache.ibatis">
        <level value="info"/>
    </logger>
    <root>
        <level value="debug"/>
        <appender-ref ref="STDOUT"/>
    </root>
</log4j:configuration>

• 2、将原始文件的前三行修改成如下内容
  

<?xml version="1.0" encoding="GB2312" ?>
<!DOCTYPE log4j:configuration SYSTEM "http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/doc-files/log4j.dtd">

<log4j:configuration debug="true">

成功解决报错，拿走不谢，不喜勿喷，欢迎关注！！！