干掉com.mchange.v2.log.MLog 的日志

近期的项目里使用到了c3p0，在创建ComboPooledDataSource类时会输出一堆日志，而且竟然是用System.err.println输出的，实在是令人不爽。

一堆日志

2013-10-22 14:53:56 com.mchange.v2.log.MLog 
信息: MLog clients using java 1.4+ standard logging.
2013-10-22 14:53:56 com.mchange.v2.c3p0.C3P0Registry banner
信息: Initializing c3p0-0.9.2-pre8 [built 19-December-2012 15:00:02 +0000; debug? true; trace: 10]
2013-10-22 14:53:56 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> true, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 1hge0yq8x1puwc6y1d8sp6v|e70e30, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge0yq8x1puwc6y1d8sp6v|e70e30, idleConnectionTestPeriod -> 20, initialPoolSize -> 5, jdbcUrl -> jdbc:mysql://127.0.0.1:3306/douniu?useUnicode=true&characterEncoding=utf8, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 100, maxStatements -> 200, maxStatementsPerConnection -> 0, minPoolSize -> 1, numHelperThreads -> 5, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> true, testConnectionOnCheckout -> true, unreturnedConnectionTimeout -> 60, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]

与之奋战了一下午，终于把他搞掉了，记录过程如下：

1.反编译mchange-commons-java-0.2.3.3.jar发现其中一句是在com.mchange.v2.log.MLog内

    logger = getLogger(MLog.class);
    String loggerDesc = mlog.getClass().getName();
    if ("com.mchange.v2.log.jdk14logging.Jdk14MLog".equals(loggerDesc))
      loggerDesc = "java 1.4+ standard";
    else if ("com.mchange.v2.log.log4j.Log4jMLog".equals(loggerDesc)) {
      loggerDesc = "log4j";
    }
    if (logger.isLoggable(MLevel.INFO)) {
      logger.log(MLevel.INFO, "MLog clients using " + loggerDesc + " logging."); //这一句在前面的日志里出现过
    }

2.由getLogger方法追查到三个重载的抽象方法getMLogger，而方法在com.mchange.v2.log.jdk14logging.Jdk14MLog中实现

  public synchronized MLogger getMLogger(String name) {
    name = name.intern();

    MLogger out = (MLogger)this.namedLoggerMap.get(name);
    if (out == null)
    {
      Logger lg = Logger.getLogger(name);
      out = new Jdk14MLogger(lg);
      this.namedLoggerMap.put(name, out);
    }
    return out;
  }

  public synchronized MLogger getMLogger(Class cl) {
    return getLogger(cl.getName());
  }

  public synchronized MLogger getMLogger()
  {
    if (this.global == null)
      this.global = new Jdk14MLogger(LogManager.getLogManager().getLogger("global"));
    return this.global;
  }

这里的Jdk14MLogger是com.mchange.v2.log.jdk14logging.Jdk14MLog的成员类，在此找到了第一步中调用的isLoggable方法

    public boolean isLoggable(MLevel l) {
      return this.logger.isLoggable(level(l));
    }

    private static Level level(MLevel lvl) {
      return (Level)lvl.asJdk14Level(); //Level是java.util.logging.Level
    }

3.由asJdk14Level方法追查到com.mchange.v2.log.MLevel

  Object level;
  public Object asJdk14Level() {
    return this.level;
  }

4.知道了以上信息之后即可以对其进行修改了，由于level变量限包内访问，所以要在自己的项目里面创建同名包之后再创建类如下：

package com.mchange.v2.log;

import java.util.logging.Level;

import com.mchange.v2.log.MLevel;

/**
 * 为减少日志而添加的类，不要修改包名
 */
public class ModifyLogLevel {
	
	public static void modifyInfoLevel(Level level) {
		MLevel.INFO.level=level;
	}
	
}

5.在主方法调用一下此方法后就看不到烦人的日志了

public class MainServer {
	static {
		ModifyLogLevel.modifyInfoLevel(Level.ALL);
	}		
}

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结：在网上没找到好的方法，所以才折腾了一个如此纠结的方法。如果您有更好的办法，恳请提点。

参考资料：

http://jingyan.baidu.com/article/642c9d34d00d8c644a46f79c.html

http://lavasoft.blog.51cto.com/62575/184492/