虽然log4j2 自带了很多种Appender 但是有时候避免不了不是自己想要的，这时候我们就需要自定义Appender，使日志输出到我们指定的位置，废话少说，上菜！
package com.hbzx.log;import java.io.Serializable;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;import org.apache.logging.log4j.core.Filter;import org.apache.logging.log4j.core.Layout;import org.apache.logging.log4j.core.LogEvent;import org.apache.logging.log4j.core.appender.AbstractAppender;import org.apache.logging.log4j.core.appender.AppenderLoggingException;import org.apache.logging.log4j.core.config.plugins.Plugin;import org.apache.logging.log4j.core.config.plugins.PluginAttribute;import org.apache.logging.log4j.core.config.plugins.PluginElement;import org.apache.logging.log4j.core.config.plugins.PluginFactory;import org.apache.logging.log4j.core.layout.PatternLayout;import com.hbzx.frame.MainFrame;/** * 自定义Appender，继承 AbstractAppender 只需要覆盖自已想要的方法即可 * 类上面的注解是用来设置配置文件中的标签。 */@Plugin(name = "TextArea", category = "Core", elementType = "appender", printObject = true)public class TextAreaAppender extends AbstractAppender { /** * @fields serialVersionUID */ private static final long serialVersionUID = -830237775522429777L; private final ReadWriteLock rwLock = new ReentrantReadWriteLock(); private final Lock readLock = rwLock.readLock(); //需要实现的构造方法，直接使用父类就行 protected TextAreaAppender(final String name, final Filter filter, final Layout layout, final boolean ignoreExceptions) { super(name, filter, layout, ignoreExceptions); } @Override public void append(LogEvent event) { readLock.lock(); try { final byte[] bytes = getLayout().toByteArray(event);//日志二进制文件，输出到指定位置就行 //下面这个是要实现的自定义逻辑 MainFrame.log(new String(bytes)); } catch (Exception ex) { if (!ignoreExceptions()) { throw new AppenderLoggingException(ex); } } finally { readLock.unlock(); } } // 下面这个方法可以接收配置文件中的参数信息 @PluginFactory public static TextAreaAppender createAppender(@PluginAttribute("name") String name, @PluginElement("Filter") final Filter filter, @PluginElement("Layout") Layout layout, @PluginAttribute("ignoreExceptions") boolean ignoreExceptions) { if (name == null) { LOGGER.error("No name provided for MyCustomAppenderImpl"); return null; } if (layout == null) { layout = PatternLayout.createDefaultLayout(); } return new TextAreaAppender(name, filter, layout, ignoreExceptions); }} 接下来就是配置文件中的信息了！
C:/logs/project.log