7-log4j2之自定义Appender

一、添加Maven依赖

<dependencies>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>${log4j.version}</version>
        </dependency>
  </dependencies>

二、自定义Appender

package com.weidai.zm.logger;

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.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 java.io.Serializable;

/**
 * @author : zhangyanqing
 * @time : 2017/12/10
 * @desc : 自定义Appender
 */
@Plugin(name="ConsoleArea", category = "core",elementType = "appender", printObject = true)
public class MyAppender extends AbstractAppender{
    public MyAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout, final boolean ignoreExceptions) {
        super(name, filter, layout,ignoreExceptions);
    }

    @Override
    public void append(LogEvent logEvent) {
        System.out.println("[My Appender] "+logEvent.getLoggerName()+"=>"+logEvent.getMessage());
    }
    @PluginFactory
    public static MyAppender createAppender(@PluginAttribute("name") String name,
                                                  @PluginElement("Filter") final Filter filter,
                                                  @PluginElement("Layout") Layout<? extends Serializable> 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 MyAppender(name, filter, layout, ignoreExceptions);
    }

}

三、log4j2.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <properties>
        <Property name="console-pattern">%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] [%level] %logger{36} - %msg%n</Property>
    </properties>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="${console-pattern}" />
        </Console>
    </Appenders>

    <Loggers>
        <Root level="info">
            <AppenderRef ref="Console" />
        </Root>
    </Loggers>
</Configuration>

四、测试代码

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * @author : zhangyanqing
 * @time : 2017/12/9
 * @desc : 根控制器日志测试
 */
public class ConsoleLoggerTest {
    public static final Logger LOGGER = LogManager.getLogger(LogManager.ROOT_LOGGER_NAME);
    public static void main(String[] args){
        LOGGER.trace("trace level");
        LOGGER.debug("debug level");
        LOGGER.info("info level");
        LOGGER.warn("warn level");
        LOGGER.error("error level");
        LOGGER.fatal("fatal level");

    }
}