apache logger 使用
apache common logging也是一个比较有名的log包。其实它只是简单封装了一些现有的log框架。
1. 只是一个框架
2. 如果有 commons-logging.properties 配置文件， 可以用它来配置使用哪个框架，以及各个框架的优先级
3. 如果没有上述文件，会搜索系统中现在的日志框架，优先是log4j, 然后是 jdk 的logger
4. 如果连jdk logger都没有，可以使用自带的 simplelog, 将所有的Log实例的日志输出到 System.out中
java -D org.apache.commons.logging.Log=org.apache.commons.logging.impl.SimpleLog ...
如果使用jdk的logger,可以建logging.properties文件，在里面进行配置，例子如下：
# handlers
handlers=java.util.logging.FileHandler, java.util.logging.ConsoleHandler
# general level
# 7个级别，从高到低分别为：SEVERE，WARNING，INFO，CONFIG，FINE，FINER，FINEST 还可以为ALL和OFF
.level=INFO，比设置低的将不输出
# file handler
java.util.logging.FileHandler.pattern = %h/java%u.log
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 1
java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter
java.util.logging.FileHandler.append ＝ true
# console handler
java.util.logging.ConsoleHandler.level = FINEST
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
test.de.jayefem.log4e.logkits.JDK1_4_Logging.level = FINEST
可以参考 jre/lib 下的同名文件。
代码里：
static Log log = LogFactory.getLog(this.class); //作为类的静态成员
log.info("...");
log.debug("");
一般来说，要用debug，应将level设为 fine 以下。
- java.util.logging.FileHandler.level specifies the default level for the Handler (defaults to Level.ALL).
- java.util.logging.FileHandler.filter specifies the name of a Filter class to use (defaults to no Filter).
- java.util.logging.FileHandler.formatter specifies the name of a Formatter class to use (defaults to java.util.logging.XMLFormatter)
- java.util.logging.FileHandler.encoding the name of the character set encoding to use (defaults to the default platform encoding).
- java.util.logging.FileHandler.limit specifies an approximate maximum amount to write (in bytes) to any one file. If this is zero, then there is no limit. (Defaults to no limit).
- java.util.logging.FileHandler.count specifies how many output files to cycle through (defaults to 1).
- java.util.logging.FileHandler.pattern specifies a pattern for generating the output file name. See below for details. (Defaults to "%h/java%u.log").
- java.util.logging.FileHandler.append specifies whether the FileHandler should append onto any existing files (defaults to false).
A pattern consists of a string that includes the following special components that will be replaced at runtime:
- "/" the local pathname separator
- "%t" the system temporary directory
- "%h" the value of the "user.home" system property
- "%g" the generation number to distinguish rotated logs
- "%u" a unique number to resolve conflicts
- "%%" translates to a single percent sign "%"