- 浏览: 226109 次
- 性别:
- 来自: 深圳
最新评论
-
xqying90:
啥子哟~
div屏幕居中的方法 -
ydc919:
JavaBeansDataExchange could not instantiate result class -
yongtree:
也太不全了啊,js呢
jquery选中单选框、复选框、下拉框 -
awindbird:
希望好用。
android ERROR: unknown virtual device name -
fangwei:
xgj1988 写道 有何高见
div屏幕居中的方法
转载自 log4j官网 http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/PatternLayout.html
org.apache.log4j
Class PatternLayout
java.lang.Object org.apache.log4j.Layout org.apache.log4j.PatternLayout
public class PatternLayout
A flexible layout configurable with pattern string.
The goal of this class is to format
a LoggingEvent
and return the results as a String. The results depend on the conversion pattern.
The conversion pattern is closely related to the conversion pattern of the printf function in C. A conversion pattern is composed of literal text and format control expressions called conversion specifiers.
You are free to insert any literal text within the conversion pattern.
Each conversion specifier starts with a percent sign (%) and is followed by optional format modifiers and a conversion character. The conversion character specifies the type of data, e.g. category, priority, date, thread name. The format modifiers control such things as field width, padding, left and right justification. The following is a simple example.
Let the conversion pattern be "%-5p [%t]: %m%n" and assume that the log4j environment was set to use a PatternLayout. Then the statements
Category root = Category.getRoot(); root.debug("Message 1"); root.warn("Message 2");
would yield the output
DEBUG [main]: Message 1 WARN [main]: Message 2
Note that there is no explicit separator between text and conversion specifiers. The pattern parser knows when it has reached the end of a conversion specifier when it reads a conversion character. In the example above the conversion specifier %-5p means the priority of the logging event should be left justified to a width of five characters. The recognized conversion characters are
c | Used to output the category of the logging event. The category conversion specifier can be optionally followed by precision specifier, that is a decimal constant in brackets.
If a precision specifier is given, then only the corresponding number of right most components of the category name will be printed. By default the category name is printed in full. For example, for the category name "a.b.c" the pattern %c{2} will output "b.c". |
C | Used to output the fully qualified class name of the caller issuing the logging request. This conversion specifier can be optionally followed by precision specifier, that is a decimal constant in brackets.
If a precision specifier is given, then only the corresponding number of right most components of the class name will be printed. By default the class name is output in fully qualified form. For example, for the class name "org.apache.xyz.SomeClass", the pattern %C{1} will output "SomeClass". WARNING Generating the caller class information is slow. Thus, it's use should be avoided unless execution speed is not an issue. |
d | Used to output the date of the logging event. The date conversion specifier may be followed by a date format specifier enclosed between braces. For example, %d{HH:mm:ss,SSS} or%d{dd MMM yyyy HH:mm:ss,SSS}. If no date format specifier is given then ISO8601 format is assumed.
The date format specifier admits the same syntax as the time pattern string of the For better results it is recommended to use the log4j date formatters. These can be specified using one of the strings "ABSOLUTE", "DATE" and "ISO8601" for specifying These dedicated date formatters perform significantly better than |
F | Used to output the file name where the logging request was issued.
WARNING Generating caller location information is extremely slow. It's use should be avoided unless execution speed is not an issue. |
l | Used to output location information of the caller which generated the logging event.
The location information depends on the JVM implementation but usually consists of the fully qualified name of the calling method followed by the callers source the file name and line number between parentheses. The location information can be very useful. However, it's generation is extremely slow. It's use should be avoided unless execution speed is not an issue. |
L | Used to output the line number from where the logging request was issued.
WARNING Generating caller location information is extremely slow. It's use should be avoided unless execution speed is not an issue. |
m | Used to output the application supplied message associated with the logging event. |
M | Used to output the method name where the logging request was issued.
WARNING Generating caller location information is extremely slow. It's use should be avoided unless execution speed is not an issue. |
n | Outputs the platform dependent line separator character or characters.
This conversion character offers practically the same performance as using non-portable line separator strings such as "\n", or "\r\n". Thus, it is the preferred way of specifying a line separator. |
p | Used to output the priority of the logging event. |
r | Used to output the number of milliseconds elapsed from the construction of the layout until the creation of the logging event. |
t | Used to output the name of the thread that generated the logging event. |
x | Used to output the NDC (nested diagnostic context) associated with the thread that generated the logging event. |
X |
Used to output the MDC (mapped diagnostic context) associated with the thread that generated the logging event. The X conversion character must be followed by the key for the map placed between braces, as in%X{clientNumber} where See |
% | The sequence %% outputs a single percent sign. |
By default the relevant information is output as is. However, with the aid of format modifiers it is possible to change the minimum field width, the maximum field width and justification.
The optional format modifier is placed between the percent sign and the conversion character.
The first optional format modifier is the left justification flag which is just the minus (-) character. Then comes the optional minimum field width modifier. This is a decimal constant that represents the minimum number of characters to output. If the data item requires fewer characters, it is padded on either the left or the right until the minimum width is reached. The default is to pad on the left (right justify) but you can specify right padding with the left justification flag. The padding character is space. If the data item is larger than the minimum field width, the field is expanded to accommodate the data. The value is never truncated.
This behavior can be changed using the maximum field width modifier which is designated by a period followed by a decimal constant. If the data item is longer than the maximum field, then the extra characters are removed from the beginning of the data item and not from the end. For example, it the maximum field width is eight and the data item is ten characters long, then the first two characters of the data item are dropped. This behavior deviates from the printf function in C where truncation is done from the end.
Below are various format modifier examples for the category conversion specifier.
%20c | false | 20 | none | Left pad with spaces if the category name is less than 20 characters long. |
%-20c | true | 20 | none | Right pad with spaces if the category name is less than 20 characters long. |
%.30c | NA | none | 30 | Truncate from the beginning if the category name is longer than 30 characters. |
%20.30c | false | 20 | 30 | Left pad with spaces if the category name is shorter than 20 characters. However, if category name is longer than 30 characters, then truncate from the beginning. |
%-20.30c | true | 20 | 30 | Right pad with spaces if the category name is shorter than 20 characters. However, if category name is longer than 30 characters, then truncate from the beginning. |
Below are some examples of conversion patterns.
The above text is largely inspired from Peter A. Darnell and Philip E. Margolis' highly recommended book "C -- a Software Engineering Approach", ISBN 0-387-97389-3.
发表评论
-
Java security KeyStore Cipher
2011-12-23 07:42 1380http://docs.oracle.com/javase/7 ... -
DirectInfo.GetFiles 排序
2011-10-19 15:50 2036The order in which this funct ... -
linux 实时观察文件行数变化
2011-09-16 17:48 2058#watch --interval=1 wc -l 20110 ... -
org.apache.poi 读取 excel xls xlsx
2011-08-30 09:56 8624http://poi.apache.org/download. ... -
mysql 列转行 GROUP_CONCAT
2011-08-09 18:36 3048GROUP_CONCAT(expr) 该函数返回 ... -
MMS 多媒体短信服务 彩信
2011-06-02 14:54 1364MMS为Multimedia Messaging Servic ... -
SMS的体系结构
2011-06-02 14:29 1622GSM标准中定义的点-点短消息服务使得短消息能在移动台和短消息 ... -
C# 事件 EventHanlder
2011-05-25 11:26 1043using System; public class ... -
linux shell 根据目录拼出 java classpath
2011-03-28 11:21 1202#ls /demo/lib a.jar b.jar ... -
apache resin 端口关联
2011-03-13 15:24 950/etc/apache2/httpd.conf ResinC ... -
ubuntu 用户相关
2011-03-12 10:06 0修改用户默认组 usermod -g sms fangwei ... -
传递带空格的参数给linux shell中的java命令
2011-01-14 17:23 3835比如说 $ test.sh "2011-01-01 ... -
ubuntu server版配置关闭系统自动更新
2011-01-11 16:37 4320修改/etc/apt/apt.conf.d/50unat ... -
tomcat配置https ssl
2010-12-14 22:09 1099生成证书文件.keystore E:\>$JAVA_H ... -
junit4定义测试集TestSuite Declaration
2009-09-11 12:26 4969转载自 Joe Ocampo http://ww ... -
jquery选中单选框、复选框、下拉框
2009-09-10 14:39 6315转载自 jquery1.3中文参考 http:// ... -
使用<!-- //-->这样的html注释把js代码注起来的作用
2009-09-02 22:18 4854一直不明白用eclipse代码提示功能生成<script ... -
Runtime.getRuntime().exec(cmd)的超时处理
2009-08-17 18:22 4225在使用Runtime.getRuntime().exec(cm ... -
从结构化编程到面向对象编程
2009-08-11 18:08 1235本文所讨论的话题 通常在一个业务系统中会有各种不同的角色,而 ... -
div屏幕居中的方法
2009-08-07 22:28 22570<style type="text/css&q ...
相关推荐
《log4j中文手册》是Java开发人员必备的参考资料,它详细介绍了log4j这个广泛使用的日志记录框架。Log4j是Apache软件基金会开发的一个开源项目,主要用于生成应用程序运行时的日志信息,帮助开发者进行调试、性能...
- `log4j.appender.*.layout`:指定appender使用的布局器,如`log4j.appender.FILE.layout=org.apache.log4j.PatternLayout`。 - `log4j.appender.*.layout.ConversionPattern`:设置布局器的转换模式,控制日志输出...
本手册将深入探讨Log4j的核心概念、配置方式以及实际应用。 **1. Log4j的核心组件** - **Logger(日志器)**: 是日志信息的来源,通过Logger类创建实例,向指定级别输出日志信息。 - **Appender(输出器)**: 负责...
### Log4J完全使用手册 #### 一、Log4J简介与重要性 Log4J是一种广泛应用于Java应用程序中的日志记录工具。它为开发者提供了一种方便且强大的方式来控制程序的日志输出,这对于软件开发过程中的调试、错误追踪以及...
### Log4j手册详解 #### 1. 概述与主要组件 Log4j是一款功能强大的日志框架,用于简化应用程序中的日志记录过程。它提供了灵活的日志记录功能,允许开发者根据不同的需求和场景调整日志的输出级别、格式以及目的地...
手册详细介绍了log4j这一强大的日志记录框架,帮助开发者理解和掌握如何在Java应用中有效、灵活地进行日志管理。 一、Log4j简介 Log4j是一款开源的Java日志记录工具,最初由Apache软件基金会开发,现已成为Apache ...
"Log4j简明手册"提供了关于这个强大日志框架的详细指南,适合初学者和经验丰富的开发者。通过学习手册,你可以了解如何配置和使用Log4j,提升你的日志管理能力,从而更好地调试和监控你的Java应用。阅读"log4j简明...
《log4j使用完全手册》是一本详细的指南,旨在帮助开发者深入理解和有效利用log4j这一广泛使用的日志记录框架。log4j是Apache软件基金会的一个项目,它为Java应用程序提供了一个灵活的日志系统,允许开发者调整日志...
### log4j基础使用手册知识点解析 #### 一、简介 **1.1 概述** Log4j是一个开源的日志记录工具,广泛应用于Java应用程序中。它允许开发者以一种非常灵活的方式记录日志信息,这有助于后续的问题诊断以及系统的...
这篇文档是基于Jakarta-log4j-1.2.8版本的官方手册翻译而成,旨在为中文用户提供详细的理解和使用指南。 Log4j的核心组件包括记录器(Loggers)、输出源(Appenders)和布局器(Layouts): 1. 记录器(Loggers)...
第四步,为了在代码中使用Log4j,我们需要在类中引入`Log`对象。通常使用`LogFactory.getLog(getClass())`来获取与当前类关联的`Log`实例,然后在适当的地方调用`log.debug("System ....")`等方法来输出日志。 Log4...
Log4j支持多种布局模式,如PatternLayout、XMLLayout和HTMLLayout等,开发者可以根据需要选择合适的布局。例如,PatternLayout允许自定义输出格式,可以包含日期、级别、线程名、类名等信息。 Log4j的灵活性还体现...
**Log4j中文手册概述** Log4j是Java编程语言中的一个强大且灵活的日志记录框架,由Apache软件基金会开发并维护。它为开发者提供了一种高效、可配置的方式来记录应用程序运行过程中的各种信息,包括错误、警告、调试...
### Log4j 使用手册知识点详解 #### 一、概述 **Log4j** 是一个用于Java应用程序的日志记录工具,由Apache软件基金会提供。它允许开发者以不同的方式记录日志信息,这些信息对于调试和故障排查非常有用。通过Log4j...
**Log4j简介** Log4j是Apache组织提供的一款开源的日志记录框架...提供的文档如"Log4j配置手册.doc"和"Log4j 配置参数 - Java - Blue Dreams.mht"将进一步深入讲解Log4j的配置与实践,对于理解和使用Log4j非常有帮助。
#### 四、Web 应用中的 Log4j 示例 示例代码展示了如何在 Web 应用中初始化 Log4j 并进行配置: ```java package net.ijsp.log4j; import org.apache.log4j.PropertyConfigurator; import javax.servlet....
通过这个CHM格式的Log4j手册,开发者可以详细学习Log4j的各种功能和用法,从而在实际开发中充分利用其优势,提高代码的可维护性和问题定位能力。同时,了解如何正确配置和优化日志系统对于任何Java开发者来说都是...