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 <clinit>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);}}———————————————————————————–
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：
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，经验是由痛苦中粹取出来的
