java_log4j 经典配置

 程序加载制定日志文件

public static final String log4j = "log4j.xml";

    /**
     * @declare 加载log4j
     * @throws IOException
     * @author cphmvp
     */
    private static void loadLog4j() throws IOException {
        Properties p = new Properties();
        InputStream is = null;
        is = ClassLoader.getSystemResourceAsStream(log4j);
        p.load(is);
        PropertyConfigurator.configure(p);// 路径
        is.close();
    }

较为简单的 ：log4j.properties 日志区分不细

#log4j.rootLogger =DEBUG,Console
log4j.rootLogger =info,LogFile,Console
  
# Output the log info to the Java Console
log4j.appender.Console = org.apache.log4j.ConsoleAppender
log4j.appender.Console.Target = System.out
log4j.appender.Console.ImmediateFlush = true
log4j.appender.Console.Threshold = INFO
log4j.appender.Console.layout = org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} %-5p %x -%m%n

# Save the log info to the log file one day.
log4j.appender.LogFile = org.apache.log4j.DailyRollingFileAppender
log4j.appender.LogFile.File = ./logs/error.log
log4j.appender.LogFile.Append = true
log4j.appender.LogFile.ImmediateFlush = true
log4j.appender.LogFile.Threshold = INFO
log4j.appender.LogFile.Encoding = UTF-8
log4j.appender.LogFile.layout = org.apache.log4j.PatternLayout
log4j.appender.LogFile.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} -[%-t] %-5p %-4c %x -%m%n

log4j.logger.httpclient.wire.header=ERROR
log4j.logger.httpclient.wire.content=ERROR
log4j.logger.org.apache.commons.httpclient = ERROR
# Set framework log level is debug  
log4j.logger.java.sql=ERROR
#log4j.logger.org.springframework.jdbc.core=DEBUG
#log4j.logger.com.opensymphony.oscache.base=DEBUG
org.apache.http.client.protocol=ERROR
# log4j.logger.org.springframework.security=DEBUG
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

较为完善的： 区分级别，可根据不同组织制定不同日志输出的 log4j.xml

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'>
    <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%t] %d{yyyy.MM.dd HH:mm:ss} %5p  - %m%n" />
        </layout>
    </appender>
    <!--***********************************crawler日志 ********************************** -->
    <!--****INFO级别***** -->
    <appender name="crawler_infoLog" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="./logs/crawler_info.log" />
        <param name="maxFileSize" value="2000KB" />
        <param name="maxBackupIndex" value="10" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%t] %d{yyyy.MM.dd HH:mm:ss} %5p  - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="INFO" />
            <param name="LevelMin" value="INFO" />
        </filter>
    </appender>


    <!--****WARN级别***** -->
    <appender name="crawler_warnLog" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="./logs/crawler_warn.log" />
        <param name="maxFileSize" value="2000KB" />
        <param name="maxBackupIndex" value="10" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%t] %d{yyyy.MM.dd HH:mm:ss} %5p  - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="WARN" />
            <param name="LevelMin" value="WARN" />
        </filter>
    </appender>
    <!--****REEOR级别***** -->
    <appender name="crawler_errorLog" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="./logs/crawler_error.log" />
        <param name="maxFileSize" value="2000KB" />
        <param name="maxBackupIndex" value="10" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%t] %d{yyyy.MM.dd HH:mm:ss} %5p  - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="ERROR" />
            <param name="LevelMin" value="ERROR" />
        </filter>
    </appender>
    <!--****FATAL级别***** -->
    <appender name="crawler_fatalLog" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="./logs/crawler_fatal.log" />
        <param name="maxFileSize" value="2000KB" />
        <param name="maxBackupIndex" value="10" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%t] %d{yyyy.MM.dd HH:mm:ss} %5p  - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="FATAL" />
            <param name="LevelMin" value="FATAL" />
        </filter>
    </appender>

    <!-- 记录该包下所有日志 -->
    <logger name="org.apache">
        <level value="INFO" />
        <appender-ref ref="stdout" />
        <appender-ref ref="crawler_infoLog" />
        <appender-ref ref="crawler_warnLog" />
        <appender-ref ref="crawler_errorLog" />
        <appender-ref ref="crawler_fatalLog" />
    </logger>
    <logger name="com.alibaba.druid">
        <level value="INFO" />
        <appender-ref ref="stdout" />
        <appender-ref ref="crawler_infoLog" />
        <appender-ref ref="crawler_warnLog" />
        <appender-ref ref="crawler_errorLog" />
        <appender-ref ref="crawler_fatalLog" />
    </logger>


    <logger name="com.loongtao.dmscrawler">
        <level value="INFO" />
        <appender-ref ref="stdout" />
        <appender-ref ref="crawler_infoLog" />
        <appender-ref ref="crawler_warnLog" />
        <appender-ref ref="crawler_errorLog" />
        <appender-ref ref="crawler_fatalLog" />
    </logger>


</log4j:configuration>  

 记录日志写法 ，error 级别的 logger.error(e.getMessage(),e);  【能显示详尽的信息，符合sona的语法检查 】