question: 
 the printed result of my log is as follows: 
 [main] INFO Test-API input parameter = 
I want to get a log like this: f9e287fad9e84cff8b2c2f2ed92adbe6 [main] INFO Test-API input parameter
 1. My test class 
 import org.apache.log4j.MDC; 
 import org.slf4j.Logger; 
 import org.slf4j.LoggerFactory; 
public class Test {
static Logger logger = LoggerFactory.getLogger(Test.class);
public static void main(String[] args) {
    MDC.clear();
    MDC.put("logid", "f9e287fad9e84cff8b2c2f2ed92adbe6");
    MDC.put("merchant_id", 1);
    MDC.put("siteName", "");
    MDC.put("userName", "userwyh");
    MDC.put("mobile", "110");
    MDC.put("mchId", 12);
    MDC.put("mchName", "");
    logger.info("===");
}
2. My log4j profile:
 log4j.rootLogger=INFO, stdout 
 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 {yy/MM/dd HH:mm:ss}% p% c {2}:% m% n 
 log4j.logger.com.rong360.crawler=info,console,info,warn,error,fatal 
 logging.path=e:/logs/crawler-meituan/logs 
 log4j.appender.console=org.apache.log4j.ConsoleAppender 
 log4j.appender.console.layout=org.apache.log4j.PatternLayout 
 log4j.appender.console.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss,SSS} [% p] [% l] [% tblog% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.console.Threshold=INFO 
 log4j.appender.debug=com.rong360.crawler.log4j.Rong360DailyRollingFileAppender 
 log4j.appender.debug.layout=org.apache.log4j.PatternLayout 
 log4j.appender.debug.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss, SSS} [% p] [% l] [% turi% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.debug.Threshold = DEBUG 
 log4j.appender.debug.append=true 
 log4j.appender.debug.File=debug.log 
 log4j.appender.info=com.rong360.crawler.log4j.Rong360DailyRollingFileAppender 
 log4j.appender.info.layout=org.apache.log4j.PatternLayout 
 log4j.appender.info.append=true 
 log4j.appender.info.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss, SSS} [% p] [% l] [% logid% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.info.Threshold = INFO 
 log4j.appender.info.File=info.log 
 log4j.appender.warn=com.rong360.crawler.log4j.Rong360DailyRollingFileAppender 
 log4j.appender.warn.layout=org.apache.log4j.PatternLayout 
 log4j.appender.warn.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss, SSS} [% p] [% l] [% turi% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.warn.Threshold = WARN 
 log4j.appender.warn.append=true 
 log4j.appender.warn.File=warn.log 
 log4j.appender.error=com.rong360.crawler.log4j.Rong360DailyRollingFileAppender 
 log4j.appender.error.layout=org.apache.log4j.PatternLayout 
 log4j.appender.error.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss, SSS} [% p] [% l] [% turi% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.error.Threshold = ERROR 
 log4j.appender.error.append=true 
 log4j.appender.error.File=error.log 
 log4j.appender.fatal=com.rong360.crawler.log4j.Rong360DailyRollingFileAppender 
 log4j.appender.fatal.layout=org.apache.log4j.PatternLayout 
 log4j.appender.fatal.layout.ConversionPattern=%-d {yyyy-MM-dd HH:mm:ss, SSS} [% p] [% l] [% turi% r] [% X {logid}] [% X {ip}] [% X {uri}] [% X {merchant_id}] [% X {user_id}]% m% n 
 log4j.appender.fatal.Threshold = FATAL 
 log4j.appender.fatal.append=true 
 log4j.appender.fatal.File=fatal.log 
