log4j的日志使用方式

创建一个maven项目。
在pom.xml中

<dependency>            <groupId>log4j</groupId>            <artifactId>log4j</artifactId>            <version>1.2.16</version></dependency>

导入jar包

log4j.properties

配置文件放在src/main/resources下，名称固定，不可随意更改。
第一行的级别设置：从高到底ERROR, WARN, INFO,DEBUG
日志文件输出：./logs/access.log
控制台输出格式：%d{yyyy-MM-dd HH:mm:ss} [%p] %l %m %n

log4j.rootLogger=debug,console, filelog4j.appender.console=org.apache.log4j.ConsoleAppenderlog4j.appender.console.layout=org.apache.log4j.PatternLayoutlog4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [%p] %l %m %nlog4j.appender.file=org.apache.log4j.DailyRollingFileAppenderlog4j.appender.file.File=./logs/access.loglog4j.appender.file.DatePattern='_'yyyyMMdd'.log'log4j.appender.file.encoding=UTF-8log4j.appender.file.layout=org.apache.log4j.PatternLayoutlog4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [%p] %l %m%nlog4j.appender.file.Append=true

package com.zhiyou.util;import java.io.InputStream;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.Properties;import javax.sql.DataSource;import org.apache.log4j.Logger;import com.alibaba.druid.pool.DruidDataSourceFactory;/** * 数据库相关操作 *  * @author jack 1.获取数据库连接 2.释放资源 * */public class DBUtil {    private static Logger log = Logger.getLogger(DBUtil.class);    private static DataSource ds;    static {        try {            InputStream in = DBUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");            Properties props = new Properties();            props.load(in);            ds = DruidDataSourceFactory.createDataSource(props);            log.info("数据库连接池初始化成功.....");        } catch (Exception ex) {            log.error("初始化数据库连接池异常：" + ex.getMessage());        }    }    /**     * 获取数据连接     *      * @return     */    public static Connection getConnection() {        try {            Connection conn = ds.getConnection();            log.info("获取数据库连接成功!");            return conn;        } catch (SQLException e) {            log.error("获取数据库连接失败" + e.getMessage());        }        return null;    }    /**     * 释放资源     *      * @param conn     * @param pst     */    public static void close(Connection conn, PreparedStatement pst) {        try {            pst.close();        } catch (Exception e) {            e.printStackTrace();        } finally {            try {                conn.close();            } catch (Exception e) {                e.printStackTrace();            }        }    }    /**     * 释放资源     *      * @param conn     * @param pst     * @param rs     */    public static void close(Connection conn, PreparedStatement pst, ResultSet rs) {        try {            rs.close();        } catch (Exception e) {            e.printStackTrace();        } finally {            try {                pst.close();            } catch (Exception e) {                e.printStackTrace();            } finally {                try {                    conn.close();                } catch (Exception e) {                    e.printStackTrace();                }            }        }    }}