maven 项目配置日志打印以及异常日志打印问题

<dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.21</version>
</dependency>
<dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.21</version>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
    <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%d{yyyy-MM-dd HH:mm:ss}]-[%p] -[%l] - %m%n" />
        </layout>
    </appender>
    <logger name="org.springframework" additivity="false">
        <level value="warn" />
        <appender-ref ref="stdout" />
    </logger>
    <logger name="net.sf.ehcache" additivity="false">
        <level value="warn" />
        <appender-ref ref="stdout" />
    </logger>
    <root>
        <level value="info" />
        <appender-ref ref="stdout" />
    </root>
</log4j:configuration>

package com.vince.xq.kafka;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.ExecutionException;
/**
 * Hello world!
 */
public class App {
    private static final Logger log = LoggerFactory.getLogger(App.class);
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        log.info("================");
        System.out.println(1);
    }
}

try {
            int x = 1 / 0;
        } catch (Exception e) {
            log.info("=========e:{}=======", e);//正确打印
            log.info("=========e:=======" + e);//错误打印
        }