Log4J的使用

导jar包:log4j-1.2.16.jar

Log4JTest.java

package cn.itcast.log4j;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * 测试log4j 使用
 * 
 * @author seawind
 * 
 */
public class Log4JTest {

    // 创建记录器时，使用当前类 Class对象构造
    private static final Logger LOG = Logger.getLogger(Log4JTest.class);

    public static void main(String[] args) {
        // 日志记录器必须有输出目标
        BasicConfigurator.configure();// 输出到控制台

        // 设置级别
        LOG.setLevel(Level.INFO);

        // 写日志
        LOG.debug("这是调试信息");
        LOG.info("这是普通信息");
        LOG.warn("这是警告信息");
        LOG.error("这是错误信息");
    }
}

Log4JTest2.java

package cn.itcast.log4j;

import org.apache.log4j.Logger;

/**
 * 使用Log4J 配置文件
 * 
 * @author seawind
 * 
 */
public class Log4JTest2 {
    // 创建日志记录器对象
    private static final Logger LOG = Logger.getLogger(Log4JTest2.class);

    public static void main(String[] args) {
        // 自动加载 log4j.properties

        LOG.debug("配置文件输出 debug");
        LOG.info("配置文件输出 info");
        LOG.warn("配置文件输出 warn");
        LOG.error("配置文件输出 error");
    }

}

log4j.properties

# Logger
log4j.rootLogger = all, A1, A2

#Appender 
log4j.appender.A1 = org.apache.log4j.ConsoleAppender
log4j.appender.A1.target = system.err
#Layouts
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern= %-4r [%t] %-5p %c %x - %m%n

log4j.appender.A2 = org.apache.log4j.FileAppender
log4j.appender.A2.file = d:/mylog.log
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

# This is the configuring for logging displayed in the Application Server
# TRACE DEBUG INFO WARN ERROR
log4j.rootCategory=DEBUG, logfile,stdout

#stdout configure
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.err
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern= %d %p [%c] - <%m>%n

#logfile configure
log4j.appender.logfile=org.apache.log4j.DailyRollingFileAppender
log4j.appender.logfile.File=e:/logs/mybatis.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern= %d %p [%c] - <%m>%n

# Changing the log level to DEBUG when debug
log4j.logger.cn.itcast.mybatis.UserMapper=TRACE

# Control logging for other open source packages
log4j.logger.org.hibernate=ERROR

通常情况下,会导入commons-logging 包,该包中,提供了日志类接口,除了Log4J外,还可以使用别的日志技术