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！
1package com.hbzx.log; 2 3import java.io.Serializable; 4import java.util.concurrent.locks.Lock; 5import java.util.concurrent.locks.ReadWriteLock; 6import java.util.concurrent.locks.ReentrantReadWriteLock; 7 8import org.apache.logging.log4j.core.Filter; 9import org.apache.logging.log4j.core.Layout; 10import org.apache.logging.log4j.core.LogEvent; 11import org.apache.logging.log4j.core.appender.AbstractAppender; 12import org.apache.logging.log4j.core.appender.AppenderLoggingException; 13import org.apache.logging.log4j.core.config.plugins.Plugin; 14import org.apache.logging.log4j.core.config.plugins.PluginAttribute; 15import org.apache.logging.log4j.core.config.plugins.PluginElement; 16import org.apache.logging.log4j.core.config.plugins.PluginFactory; 17import org.apache.logging.log4j.core.layout.PatternLayout; 18 19import com.hbzx.frame.MainFrame; 20 21/** 22 * 自定义Appender，继承 AbstractAppender 只需要覆盖自已想要的方法即可<br> 23 * 类上面的注解是用来设置配置文件中的标签。 24 */ 25@Plugin(name = "TextArea", category = "Core", elementType = "appender", printObject = true) 26public class TextAreaAppender extends AbstractAppender { 27 28 /** 29 * @fields serialVersionUID 30 */ 31 private static final long serialVersionUID = -830237775522429777L; 32 private final ReadWriteLock rwLock = new ReentrantReadWriteLock(); 33 private final Lock readLock = rwLock.readLock(); 34 35 //需要实现的构造方法，直接使用父类就行 36 protected TextAreaAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout, 37 final boolean ignoreExceptions) { 38 super(name, filter, layout, ignoreExceptions); 39 } 40 41 @Override 42 public void append(LogEvent event) { 43 readLock.lock(); 44 try { 45 final byte[] bytes = getLayout().toByteArray(event);//日志二进制文件，输出到指定位置就行 46 //下面这个是要实现的自定义逻辑 47 MainFrame.log(new String(bytes)); 48 } catch (Exception ex) { 49 if (!ignoreExceptions()) { 50 throw new AppenderLoggingException(ex); 51 } 52 } finally { 53 readLock.unlock(); 54 } 55 } 56 57 // 下面这个方法可以接收配置文件中的参数信息 58 @PluginFactory 59 public static TextAreaAppender createAppender(@PluginAttribute("name") String name, 60 @PluginElement("Filter") final Filter filter, 61 @PluginElement("Layout") Layout<? extends Serializable> layout, 62 @PluginAttribute("ignoreExceptions") boolean ignoreExceptions) { 63 if (name == null) { 64 LOGGER.error("No name provided for MyCustomAppenderImpl"); 65 return null; 66 } 67 if (layout == null) { 68 layout = PatternLayout.createDefaultLayout(); 69 } 70 return new TextAreaAppender(name, filter, layout, ignoreExceptions); 71 } 72 73}
接下来就是配置文件中的信息了！
1<?xml version="1.0" encoding="UTF-8"?> 2<Configuration status="info" packages="com.hbzx.log"> 3 <Properties> 4 <Property name="filePath">C:/logs/project.log</Property> 5 </Properties> 6 7 <Appenders> 8 <!--这个输出控制台的配置 --> 9 <Console name="console" target="SYSTEM_OUT"> 10 <!--控制台只输出level及以上级别的信息（onMatch），其他的直接拒绝（onMismatch） --> 11 <ThresholdFilter level="DEBUG" onMatch="ACCEPT" onMismatch="DENY" /> 12 <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] [%-5p] %c {%F:%L} - %m%n" /> 13 </Console> 14 15 <File name="logFile" fileName="${filePath}"> 16 <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] [%-5p] %c {%F:%L} - %m%n" /> 17 </File> 18 19 <!-- 这个就是自定义的Appender --> 20 <TextArea name="textarea"> 21 <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] [%-5p] {%F:%L} - %m%n" /> 22 </TextArea> 23 </Appenders> 24 <Loggers> 25 <logger name="com.hbzx" level="debug" /> 26 <logger name="org.apache.http" level="info" /> 27 <logger name="org.apache.commons" level="info" /> 28 <logger name="io.netty" level="info" /> 29 <logger name="org.asynchttpclient" level="info" /> 30 31 <Root level="debug"> 32 <AppenderRef ref="console" /> 33 <AppenderRef ref="logFile" /> 34 <AppenderRef ref="textarea" /> 35 </Root> 36 </Loggers> 37</Configuration>