最近在做项目中需要用到日志,本来选取的是Log4j,最后经过对比之后还是发现LogBack在性能上比Log4j有优势。至于有什么好处,请参考下面这篇文章。
从Log4j迁移到LogBack的理由

下面废话不多说了,就看一下,如何来把LogBack集成到我们的web项目中吧。本人前台用的是SpringMVC。

jar包配置

如果要使用LogBack做为日志的插件的话,需要的jar包有如下,直接看一下Maven依赖

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.12</version>
</dependency>
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.1.3</version>
    <scope>compile</scope>
    <exclusions>
        <exclusion>
            <artifactId>slf4j-api</artifactId>
            <groupId>org.slf4j</groupId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-core</artifactId>
    <version>1.1.3</version>
    <exclusions>
        <exclusion>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </exclusion>
    </exclusions>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-access</artifactId>
    <version>1.1.3</version>
    <exclusions>
        <exclusion>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </exclusion>
    </exclusions>
    <scope>compile</scope>
</dependency>

Web.xml
在web项目中需要通过web.xml来加载我们所需要的LogBack.xml具体如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <!-- logback-begin -->
    <context-param>
        <param-name>logbackConfigLocation</param-name>
        <param-value> classpath:logback.xml</param-value>
    </context-param>
    <listener>
        <listener-class>com.util.LogbackConfigListener</listener-class>
    </listener>
    <!-- logback-end -->


    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <servlet>
        <servlet-name>springMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value> classpath:springMVC-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!-- 这里一定要是/根据Servlet规范来的 -->
    <servlet-mapping>
        <servlet-name>springMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

上面的XML中用到了自定义的监听器,分别是三个类,如下所示

LogbackConfigListener类

package com.util;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class LogbackConfigListener implements ServletContextListener {

    public void contextInitialized(ServletContextEvent event) {
        LogbackWebConfigurer.initLogging(event.getServletContext());
    }

    public void contextDestroyed(ServletContextEvent event) {
        LogbackWebConfigurer.shutdownLogging(event.getServletContext());
    }
}

LogbackConfigurer类


package com.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.net.URL;

import org.slf4j.LoggerFactory;
import org.springframework.util.ResourceUtils;
import org.springframework.util.SystemPropertyUtils;

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.joran.JoranConfigurator;
import ch.qos.logback.core.joran.spi.JoranException;

public abstract class LogbackConfigurer {

    /** Pseudo URL prefix for loading from the class path: "classpath:" */
    public static final String CLASSPATH_URL_PREFIX = "classpath:";

    /** Extension that indicates a logback XML config file: ".xml" */
    public static final String XML_FILE_EXTENSION = ".xml";

    private static LoggerContext lc = (LoggerContext) LoggerFactory
            .getILoggerFactory();
    private static JoranConfigurator configurator = new JoranConfigurator();

    /**
     * Initialize logback from the given file location, with no config file
     * refreshing. Assumes an XML file in case of a ".xml" file extension, and a
     * properties file otherwise.
     * 
     * @param location
     *            the location of the config file: either a "classpath:"
     *            location (e.g. "classpath:mylogback.properties"), an absolute
     *            file URL (e.g.
     *            "file:C:/logback.properties), or a plain absolute path in the file system (e.g. "
     *            C:/logback.properties")
     * @throws FileNotFoundException
     *             if the location specifies an invalid file path
     */
    public static void initLogging(String location)
            throws FileNotFoundException {
        String resolvedLocation = SystemPropertyUtils
                .resolvePlaceholders(location);
        URL url = ResourceUtils.getURL(resolvedLocation);
        if (resolvedLocation.toLowerCase().endsWith(XML_FILE_EXTENSION)) {
            // DOMConfigurator.configure(url);
            configurator.setContext(lc);
            lc.reset();
            try {
                configurator.doConfigure(url);
            } catch (JoranException ex) {
                throw new FileNotFoundException(url.getPath());
            }
            lc.start();
        }
        // else {
        // PropertyConfigurator.configure(url);
        // }
    }

    /**
     * Shut down logback, properly releasing all file locks.
     * <p>
     * This isn't strictly necessary, but recommended for shutting down logback
     * in a scenario where the host VM stays alive (for example, when shutting
     * down an application in a J2EE environment).
     */
    public static void shutdownLogging() {
        lc.stop();
    }

    /**
     * Set the specified system property to the current working directory.
     * <p>
     * This can be used e.g. for test environments, for applications that
     * leverage logbackWebConfigurer's "webAppRootKey" support in a web
     * environment.
     * 
     * @param key
     *            system property key to use, as expected in logback
     *            configuration (for example: "demo.root", used as
     *            "${demo.root}/WEB-INF/demo.log")
     * @see org.springframework.web.util.logbackWebConfigurer
     */
    public static void setWorkingDirSystemProperty(String key) {
        System.setProperty(key, new File("").getAbsolutePath());
    }

}

LogbackWebConfigurer类

package com.util;

import java.io.FileNotFoundException;

import javax.servlet.ServletContext;

import org.springframework.util.ResourceUtils;
import org.springframework.util.SystemPropertyUtils;
import org.springframework.web.util.WebUtils;

public abstract class LogbackWebConfigurer {

    /** Parameter specifying the location of the logback config file */
    public static final String CONFIG_LOCATION_PARAM = "logbackConfigLocation";

    /**
     * Parameter specifying the refresh interval for checking the logback config
     * file
     */
    public static final String REFRESH_INTERVAL_PARAM = "logbackRefreshInterval";

    /** Parameter specifying whether to expose the web app root system property */
    public static final String EXPOSE_WEB_APP_ROOT_PARAM = "logbackExposeWebAppRoot";

    /**
     * Initialize logback, including setting the web app root system property.
     * 
     * @param servletContext
     *            the current ServletContext
     * @see WebUtils#setWebAppRootSystemProperty
     */
    public static void initLogging(ServletContext servletContext) {
        // Expose the web app root system property.
        if (exposeWebAppRoot(servletContext)) {
            WebUtils.setWebAppRootSystemProperty(servletContext);
        }

        // Only perform custom logback initialization in case of a config file.
        String location = servletContext
                .getInitParameter(CONFIG_LOCATION_PARAM);
        if (location != null) {
            // Perform actual logback initialization; else rely on logback's
            // default initialization.
            try {
                // Return a URL (e.g. "classpath:" or "file:") as-is;
                // consider a plain file path as relative to the web application
                // root directory.
                if (!ResourceUtils.isUrl(location)) {
                    // Resolve system property placeholders before resolving
                    // real path.
                    location = SystemPropertyUtils
                            .resolvePlaceholders(location);
                    location = WebUtils.getRealPath(servletContext, location);
                }

                // Write log message to server log.
                servletContext.log("Initializing logback from [" + location
                        + "]");

                // Initialize without refresh check, i.e. without logback's
                // watchdog thread.
                LogbackConfigurer.initLogging(location);

            } catch (FileNotFoundException ex) {
                throw new IllegalArgumentException(
                        "Invalid 'logbackConfigLocation' parameter: "
                                + ex.getMessage());
            }
        }
    }

    /**
     * Shut down logback, properly releasing all file locks and resetting the
     * web app root system property.
     * 
     * @param servletContext
     *            the current ServletContext
     * @see WebUtils#removeWebAppRootSystemProperty
     */
    public static void shutdownLogging(ServletContext servletContext) {
        servletContext.log("Shutting down logback");
        try {
            LogbackConfigurer.shutdownLogging();
        } finally {
            // Remove the web app root system property.
            if (exposeWebAppRoot(servletContext)) {
                WebUtils.removeWebAppRootSystemProperty(servletContext);
            }
        }
    }

    /**
     * Return whether to expose the web app root system property, checking the
     * corresponding ServletContext init parameter.
     * 
     * @see #EXPOSE_WEB_APP_ROOT_PARAM
     */
    private static boolean exposeWebAppRoot(ServletContext servletContext) {
        String exposeWebAppRootParam = servletContext
                .getInitParameter(EXPOSE_WEB_APP_ROOT_PARAM);
        return (exposeWebAppRootParam == null || Boolean
                .valueOf(exposeWebAppRootParam));
    }

}

logback.XML配置
下面来看一下这个xml是如何配置的

<?xml version="1.0" encoding="UTF-8"?>
<!-- ROOT 节点 -->
<!-- 属性描述 scan:性设置为true时,配置文件如果发生改变,将会被重新加载,默认值为true scanPeriod:设置监测配置文件是否有修改的时间间隔,如果没有给出时间单位,默认单位是毫秒。当scan为true时,此属性生效。默认的时间间隔为1分钟。 
    debug:当此属性设置为true时,将打印出logback内部日志信息,实时查看logback运行状态。默认值为false。 -->
<configuration scan="true" scanPeriod="60 seconds" debug="false">
    <!-- 定义日志文件 输入位置,注意此处的/ -->
    <property name="log_dir" value="E:/logs" />
    <!-- 日志最大的历史 60天 -->
    <property name="maxHistory" value="60"></property>


    <!-- 控制台输出日志 -->
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger -
                %msg%n</pattern>
        </encoder>

    </appender>


    <!-- 出错日志 appender -->
    <appender name="ERROR"
        class="ch.qos.logback.core.rolling.RollingFileAppender">
        <!-- 在多数的Log工具中,级别是可以传递,例如如果指定了日志输出级别为DEBUG, 那么INFO、ERROR级别的log也会出现在日志文件。这种默认给程序的调试带来了很多的麻烦 
            通过配置Filter 来严格控制日志输入级别 <filter class="ch.qos.logback.classic.filter.LevelFilter"> 
            <level>ERROR/level> <onMatch>ACCEPT</onMatch> <onMismatch>DENY</onMismatch> 
            </filter> -->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- 按天回滚 daily -->
            <fileNamePattern>${log_dir}/error-log-%d{yyyy-MM-dd}.log
            </fileNamePattern>
            <!-- 日志最大的历史 60天 -->
            <maxHistory>${maxHistory}</maxHistory>
        </rollingPolicy>
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger -
                %msg%n</pattern>
        </encoder>
    </appender>

    <!-- INFO 日志 appender -->
    <appender name="INFO"
        class="ch.qos.logback.core.rolling.RollingFileAppender">
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- 按天回滚 daily -->
            <fileNamePattern>${log_dir}/info-log-%d{yyyy-MM-dd}.log
            </fileNamePattern>
            <!-- 日志最大的历史 60天 -->
            <maxHistory>${maxHistory}</maxHistory>
        </rollingPolicy>
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger -
                %msg%n</pattern>
        </encoder>
    </appender>


    <!-- 访问日志 appender -->
    <appender name="ACCESS"
        class="ch.qos.logback.core.rolling.RollingFileAppender">
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- 按天回滚 daily -->
            <fileNamePattern>${log_dir}/access-log-%d{yyyy-MM-dd}.log
            </fileNamePattern>
            <!-- 日志最大的历史 60天 -->
            <maxHistory>${maxHistory}</maxHistory>
        </rollingPolicy>
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger -
                %msg%n</pattern>
        </encoder>
    </appender>

    <!-- 系统用户操作日志 appender -->
    <appender name="SYS-USER"
        class="ch.qos.logback.core.rolling.RollingFileAppender">
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- 按天回滚 daily -->
            <fileNamePattern>${log_dir}/sys_user-log-%d{yyyy-MM-dd}.log
            </fileNamePattern>
            <!-- 日志最大的历史 60天 -->
            <maxHistory>${maxHistory}</maxHistory>
        </rollingPolicy>
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger -
                %msg%n</pattern>
        </encoder>
    </appender>


    <!-- 打印SQL输出 -->
    <logger name="java.sql.Connection" level="DEBUG" />
    <logger name="java.sql.Statement" level="DEBUG" />
    <logger name="java.sql.PreparedStatement" level="DEBUG" />



    <!--error错误日志 additivity="false"表示不向上传递 -->
    <!-- <logger name="com.test" level="error" > -->
    <!-- <appender-ref ref="ERROR" /> -->
    <!-- </logger> -->
    <!--info日志 -->
    <logger name="com.test" level="info" additivity="false">
        <appender-ref ref="INFO" />
    </logger>
    <!--访问日志 -->
    <!-- <logger name="com.test" level="info" additivity="false"> -->
    <!-- <appender-ref ref="ACCESS" /> -->
    <!-- </logger> -->
    <!--系统用户操作日志 -->
    <!-- <logger name="com.test" level="info" additivity="false"> -->
    <!-- <appender-ref ref="SYS-USER" /> -->
    <!-- </logger> -->

    <root>
        <level value="INFO" />
        <appender-ref ref="stdout" />
    </root>
</configuration>

关于这个XML文件的详细讲解请参考http://blog.csdn.net/haidage/article/details/6794509