自定义拓展日志

[www1350]

平常的使用过程中我们经常需要使用日志打印，有些信息比如线程信息、时间戳、日志级别等都可以用一些默认规则很容易的使用。但是如果是一些自定义的信息可能就需要拓展一下了。

Logback

简单使用

package chapters.introduction;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HelloWorld1 {

  public static void main(String[] args) {
    Logger logger = LoggerFactory.getLogger("chapters.introduction.HelloWorld1");
    logger.debug("Hello world.");

  }
}

20:49:07.962 [main] DEBUG chapters.introduction.HelloWorld1 - Hello world.

配置

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <!-- encoders are assigned the type
         ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>
  <root level="debug">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

package chapters.configuration;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Foo {
  static final Logger logger = LoggerFactory.getLogger(Foo.class);

  public void doIt() {
    logger.debug("Did it again!");
  }
}

16:06:09.031 [main] INFO chapters.configuration.MyApp1 - Entering application. 16:06:09.046 [main] DEBUG chapters.configuration.Foo - Did it again! 16:06:09.046 [main] INFO chapters.configuration.MyApp1 - Exiting application.

通过配置规则%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n来输出响应信息

logback主要由三块组成： Logger, Appender and Layout

Appender负责把日志事件的任务写入

public interface Appender<E> extends LifeCycle, ContextAware, FilterAttachable {
  public String getName();
  public void setName(String name);
  void doAppend(E event);
}

encoder将事件转换为一个字节数组

package ch.qos.logback.core.encoder;

public interface Encoder<E> extends ContextAware, LifeCycle {

   /**
   * This method is called when the owning appender starts or whenever output
   * needs to be directed to a new OutputStream, for instance as a result of a
   * rollover.
   */
  void init(OutputStream os) throws IOException;

  /**
   * Encode and write an event to the appropriate {@link OutputStream}.
   * Implementations are free to defer writing out of the encoded event and
   * instead write in batches.
   */
  void doEncode(E event) throws IOException;

  /**
   * This method is called prior to the closing of the underling
   * {@link OutputStream}. Implementations MUST not close the underlying
   * {@link OutputStream} which is the responsibility of the owning appender.
   */
  void close() throws IOException;
}

Layout负责将传入的事件转换为一个字符串

public interface Layout<E> extends ContextAware, LifeCycle {

  String doLayout(E event);
  String getFileHeader();
  String getPresentationHeader();
  String getFileFooter();
  String getPresentationFooter();
  String getContentType();
}

完全自定义layout

LayoutBase

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
      <layout class="chapters.layouts.MySampleLayout2"> 
        <prefix>MyPrefix</prefix>
        <printThreadName>false</printThreadName>
      </layout>
    </encoder>
  </appender>

  <root level="DEBUG">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

package chapters.layouts;

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.LayoutBase;

public class MySampleLayout2 extends LayoutBase<ILoggingEvent> {

  String prefix = null;
  boolean printThreadName = true;

  public void setPrefix(String prefix) {
    this.prefix = prefix;
  }

  public void setPrintThreadName(boolean printThreadName) {
    this.printThreadName = printThreadName;
  }

  public String doLayout(ILoggingEvent event) {
    StringBuffer sbuf = new StringBuffer(128);
    if (prefix != null) {
      sbuf.append(prefix + ": ");
    }
    sbuf.append(event.getTimeStamp() - event.getLoggerContextVO().getBirthTime());
    sbuf.append(" ");
    sbuf.append(event.getLevel());
    if (printThreadName) {
      sbuf.append(" [");
      sbuf.append(event.getThreadName());
      sbuf.append("] ");
    } else {
      sbuf.append(" ");
    }
    sbuf.append(event.getLoggerName());
    sbuf.append(" - ");
    sbuf.append(event.getFormattedMessage());
    sbuf.append(LINE_SEP);
    return sbuf.toString();
  }
}

PatternLayout

Logback classic附带一个叫做PatternLayout灵活的布局。所有Layout,PatternLayout负责日志事件并返回一个字符串。这个字符串可以通过调整PatternLayout定制的转换模式。

你可以在转换模式里面插入任意文字，格式都是以百分号开头，括号括起来的。比如[%thread]

创建一个自定义转换说明符

1. 继承ClassicConverter

public class MySampleConverter extends ClassicConverter {

  long start = System.nanoTime();

  @Override
  public String convert(ILoggingEvent event) {
    long nowInNanos = System.nanoTime();
    return Long.toString(nowInNanos-start);
  }
}

2. 声明转换文件

<configuration>

  <conversionRule conversionWord="nanos" 
                  converterClass="chapters.layouts.MySampleConverter" />

  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%-6nanos [%thread] - %msg%n</pattern>
    </encoder>
  </appender>

  <root level="DEBUG">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

4868695 [main] DEBUG - Everything's going well 5758748 [main] ERROR - maybe not quite...

另外一种方式

1. 继承PatternLayout，默认转换说明符号多设置一条

public class TraceIdPatternLogbackLayout extends PatternLayout {
    static {
        defaultConverterMap.put("traceId", LogbackPatternConverter.class.getName());
    }
}

2. 继承ClassicConverter

public class LogbackPatternConverter extends ClassicConverter {
    @Override
    public String convert(ILoggingEvent iLoggingEvent) {
        return Strings.isNullOrEmpty(TraceUtil.getTraceId()) ? "N/A" : TraceUtil.getTraceId();
    }
}

3. 配置自定义layout配置文件

<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
      <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
         <layout class="com.absurd.logback.TraceIdPatternLogbackLayout">
            <pattern>[%d{MM-dd HH:mm:ss.SSS}] [%traceId] [%thread] %-5level %logger[%M] - %msg%n</pattern>
         </layout>
      </encoder>
   </appender>

Log4j

简单使用

import com.foo.Bar;

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

 public class MyApp {

   // Define a static logger variable so that it references the
   // Logger instance named "MyApp".
   static Logger logger = Logger.getLogger(MyApp.class);

   public static void main(String[] args) {

     // 打印到控制台
     BasicConfigurator.configure();

     logger.info("Entering application.");
     Bar bar = new Bar();
     bar.doIt();
     logger.info("Exiting application.");
   }
 }

0 [main] INFO MyApp - Entering application. 36 [main] DEBUG com.foo.Bar - Did it again! 51 [main] INFO MyApp - Exiting application.

手动设置配置文件

 import com.foo.Bar;

 import org.apache.log4j.Logger;
 import org.apache.log4j.PropertyConfigurator;

 public class MyApp {

   static Logger logger = Logger.getLogger(MyApp.class.getName());

   public static void main(String[] args) {

     // BasicConfigurator replaced with PropertyConfigurator.
     PropertyConfigurator.configure(args[0]);

     logger.info("Entering application.");
     Bar bar = new Bar();
     bar.doIt();
     logger.info("Exiting application.");
   }
 }

屏蔽日志

log4j.rootLogger=DEBUG, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout

# Print the date in ISO 8601 format
log4j.appender.A1.layout.ConversionPattern=%d [%t] %-5p %c - %m%n

# Print only messages of level WARN or above in the package com.foo.
log4j.logger.com.foo=WARN

2000-09-07 14:07:41,508 [main] INFO MyApp - Entering application. 2000-09-07 14:07:41,529 [main] INFO MyApp - Exiting application.

多个appender

log4j.rootLogger=debug, stdout, R

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=example.log

log4j.appender.R.MaxFileSize=100KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1

log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n

INFO [main] (MyApp2.java:12) - Entering application. DEBUG [main] (Bar.java:8) - Doing it again! INFO [main] (MyApp2.java:15) - Exiting application.

自定义

public class TraceIdPatternConverter  extends PatternConverter {
    @Override
    protected String convert(LoggingEvent loggingEvent) {
        return Strings.isNullOrEmpty(TraceUtil.getTraceId()) ? "N/A" : TraceUtil.getTraceId();
    }
}

public class TraceIdPatternParser extends PatternParser {

    public TraceIdPatternParser(String pattern) {
        super(pattern);
    }

    @Override
    protected void finalizeConverter(char c) {
        if ('T' == c) {
            addConverter(new TraceIdPatternConverter());
        } else {
            super.finalizeConverter(c);
        }
    }
}

public class TraceIdPatternLayout extends PatternLayout {
    @Override
    protected PatternParser createPatternParser(String pattern) {
        return new TraceIdPatternParser(pattern);
    }
}

log4j.rootLogger=debug, stdout, R

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=com.absurd.log4j.TraceIdPatternLayout

# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%5p [%T] [%t] (%F:%L) - %m%n

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=trace.log

log4j.appender.R.MaxFileSize=100KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1

log4j.appender.R.layout=com.absurd.log4j.TraceIdPatternLayout
log4j.appender.R.layout.ConversionPattern=%p [%T] %t %c - %m%n

INFO [1524824013684_bOcv][main] (TraceTest.java:44) - Entering application. INFO [1524824013684_bOcv][main] (TraceTest.java:45) - Exiting application.