log4j2 扩展日志级别,支持将系统日志与业务处理日志拆分

　　项目中，有时候需要对系统中已处理的一些业务数据日志进行提取分析，通常log4j默认提供的日志级别可能不够用，这时候我们就需要对日志级别进行扩展，以满足我们的需求.

本文就简单介绍一下log4j2的日志级别扩展，直接上代码：

 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.message.Message;
 import org.apache.logging.log4j.message.MessageFactory;
 import org.apache.logging.log4j.spi.AbstractLogger;
 import org.apache.logging.log4j.spi.ExtendedLoggerWrapper;
 import org.apache.logging.log4j.util.MessageSupplier;
 import org.apache.logging.log4j.util.Supplier;

 /**log4j2日志扩展，支持业务日志
  * 业务日志为最高级别
  * 使用方式与扩展前基本相同：</br>
  * 使用CustomLogger  log=CustomLogger.getLogger(loggerName);</br>
  * 替代原来的：Logger log=LogManager.getLogger(loggerName);</br>
  * 记录用于数据分析的业务日志 使用log.business(msg);</br>
  * @author jessezeng
  *
  */
 public final class CustomLogger extends ExtendedLoggerWrapper {
     private static final long serialVersionUID = 103418572168532L;
     private final ExtendedLoggerWrapper logger;

     private static final String FQCN = CustomLogger.class.getName();
     private static final Level BUSINESS = Level.forName("BUSINESS", 50);

     private CustomLogger(final Logger logger) {
         super((AbstractLogger) logger, logger.getName(), logger.getMessageFactory());
         this.logger = this;
     }

     public static CustomLogger getLogger() {
         final Logger wrapped = LogManager.getLogger();
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final Class<?> loggerName) {
         final Logger wrapped = LogManager.getLogger(loggerName);
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final Class<?> loggerName, final MessageFactory factory) {
         final Logger wrapped = LogManager.getLogger(loggerName, factory);
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final Object value) {
         final Logger wrapped = LogManager.getLogger(value);
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final Object value, final MessageFactory factory) {
         final Logger wrapped = LogManager.getLogger(value, factory);
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final String name) {
         final Logger wrapped = LogManager.getLogger(name);
         return new CustomLogger(wrapped);
     }

     public static CustomLogger getLogger(final String name, final MessageFactory factory) {
         final Logger wrapped = LogManager.getLogger(name, factory);
         return new CustomLogger(wrapped);
     }

     public void business(final Marker marker, final Message msg) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msg, (Throwable) null);
     }

     public void business(final Marker marker, final Message msg, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msg, t);
     }

     public void business(final Marker marker, final Object message) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, (Throwable) null);
     }

     public void business(final Marker marker, final Object message, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, t);
     }

     public void business(final Marker marker, final String message) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, (Throwable) null);
     }

     public void business(final Marker marker, final String message, final Object... params) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, params);
     }

     public void business(final Marker marker, final String message, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, t);
     }

     public void business(final Message msg) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msg, (Throwable) null);
     }

     public void business(final Message msg, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msg, t);
     }

     public void business(final Object message) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, (Throwable) null);
     }

     public void business(final Object message, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, t);
     }

     public void business(final String message) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, (Throwable) null);
     }

     public void business(final String message, final Object... params) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, params);
     }

     public void business(final String message, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, t);
     }

     public void business(final Supplier<?> msgSupplier) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msgSupplier, (Throwable) null);
     }

     public void business(final Supplier<?> msgSupplier, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msgSupplier, t);
     }

     public void business(final Marker marker, final Supplier<?> msgSupplier) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msgSupplier, (Throwable) null);
     }

     public void business(final Marker marker, final String message, final Supplier<?>... paramSuppliers) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, message, paramSuppliers);
     }

     public void business(final Marker marker, final Supplier<?> msgSupplier, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msgSupplier, t);
     }

     public void business(final String message, final Supplier<?>... paramSuppliers) {
         logger.logIfEnabled(FQCN, BUSINESS, null, message, paramSuppliers);
     }

     public void business(final Marker marker, final MessageSupplier msgSupplier) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msgSupplier, (Throwable) null);
     }

     public void business(final Marker marker, final MessageSupplier msgSupplier, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, marker, msgSupplier, t);
     }

     public void business(final MessageSupplier msgSupplier) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msgSupplier, (Throwable) null);
     }

     public void business(final MessageSupplier msgSupplier, final Throwable t) {
         logger.logIfEnabled(FQCN, BUSINESS, null, msgSupplier, t);
     }
 }

代码实际上很简单，需要注意的地方是：

 26     private static final Level BUSINESS = Level.forName("BUSINESS", );  // 50用于指定级别

注意上面红色的数字，这个数字用于指定级别的高低，可以根据自己的需要定义不同的值，log4j2中默认级别值可以参考如下：

     OFF(0),

     FATAL(100),

     ERROR(200),

     WARN(300),

     INFO(400),

     DEBUG(500),

     TRACE(600),

     ALL(Integer.MAX_VALUE);