log4j自定义日志等级，步骤如下

1.继承logj的level类，定义一个自己的日志级别：

public class TestLevel extends Level { public TestLevel(int level, String levelStr, int syslogEquivalent) {
super(level, levelStr, syslogEquivalent);
}
}

2.继承Filter类，定义一个自己的filter：

public class MyLogFiter extends Filter {
/**
* Do we return ACCEPT when a match occurs. Default is
* <code>false</code>, so that later filters get run by default
*/
boolean acceptOnMatch = false;

int levelMin;
int levelMax;

/**
* Return the decision of this filter.
*/
@Override
public int decide(LoggingEvent event) {
int inputLevel = event.getLevel().toInt();
if (inputLevel >= levelMin && inputLevel <= levelMax) {
return Filter.ACCEPT;
}
return Filter.DENY;
}

/**
* Get the value of the <code>LevelMax</code> option.
*/
public int getLevelMax() {
return levelMax;
}

/**
* Get the value of the <code>LevelMin</code> option.
*/
public int getLevelMin() {
return levelMin;
}

/**
* Get the value of the <code>AcceptOnMatch</code> option.
*/
public boolean getAcceptOnMatch() {
return acceptOnMatch;
}

/**
* Set the <code>LevelMax</code> option.
*/
public void setLevelMax(int levelMax) {
this.levelMax = levelMax;
}

/**
* Set the <code>LevelMin</code> option.
*/
public void setLevelMin(int levelMin) {
this.levelMin = levelMin;
}

/**
* Set the <code>AcceptOnMatch</code> option.
*/
public void setAcceptOnMatch(boolean acceptOnMatch) {
this.acceptOnMatch = acceptOnMatch;
}

}
3.在不侵入log4j源代码的情况下，对log4j的logger输出进行封装，并且添加自己定义的级别的输出方法：

public class Logger {

private final static int priority = 40100;
private final org.apache.log4j.Logger logger;
private static final String FQCN;

//以下为自定义的日志级别
public static final Level PAY_LEVEL = new TestLevel(priority, “TEST”, SyslogAppender.LOG_LOCAL0);

static {
FQCN = Logger.class.getName();
}

private Logger(Class<?> clazz) {
logger = org.apache.log4j.Logger.getLogger(clazz);
}

private Logger() {
logger = org.apache.log4j.Logger.getRootLogger();
}

public static Logger getLogger(Class<?> clazz) {
return new Logger(clazz);
}

public static Logger getRootLogger() {
return new Logger();
}

public void test(Object message) {
forcedLog(logger, PAY_LEVEL, message);
}

public void test(Object message, Throwable t) {
forcedLog(logger, PAY_LEVEL, message, t);
}

private static void forcedLog(org.apache.log4j.Logger logger, Level level, Object message) {
logger.callAppenders(new LoggingEvent(FQCN, logger, level, message, null));
}

private static void forcedLog(org.apache.log4j.Logger logger, Level level, Object message, Throwable t) {
logger.callAppenders(new LoggingEvent(FQCN, logger, level, message, t));
}

}
4.修改log4j的xml配置文件,添加自定义的appender：

<appender name=”TEST”>
<param name=”File” value=”/var/Test.log”/>
<param name=”Append” value=”true”/>
<param name=”DatePattern” value=”‘.’yyyy-MM-dd-HH”/>
<param name=”BufferedIO” value=”true”/>
<!– 8K为一个写单元 –> <param name=”BufferSize” value=”8192″/> <layout>
<param name=”ConversionPattern” value=”%d{yyyy-MM-dd HH:mm:ss}\t%F\t%L\t%M\t%m%n”/>
</layout>
<filter class=”MyLogFiter”>
<param name=”LevelMin” value=”40100″/>
<param name=”LevelMax” value=”40100″/>
</filter>
</appender>

5.在需要输出日志的地方使用封装的logger输出方法即可：

logger.test(“hahaha,test”);