Eclipse and log4j configuration (detailed ~)

[1] starting from scratch

 

A). Create a Java project> Create a package> Create a Java class;

B). Import jar package (One is enough.Here I am using a log4j-1.2.14.jar,

C). Create log4j. properties and place it inProject root directory;

Log4j. rootlogger = info, serverdailyrollingfile, stdout
Log4j. appender. serverdailyrollingfile = org. Apache. log4j. dailyrollingfileappender
Log4j. appender. serverdailyrollingfile. datepattern = '. 'yyyy-mm-dd
Log4j. appender. serverdailyrollingfile. File = C: // logs/notify-subscription.log
Log4j. appender. serverdailyrollingfile. layout = org. Apache. log4j. patternlayout
Log4j. appender. serverdailyrollingfile. layout. conversionpattern = % d-% m % N
Log4j. appender. serverdailyrollingfile. append = true

Log4j. appender. stdout = org. Apache. log4j. leleappender
Log4j. appender. stdout. layout = org. Apache. log4j. patternlayout
Log4j. appender. stdout. layout. conversionpattern = % d {yyyy-mm-dd hh: mm: SS} % P [% C] % m % N

 

D). Load log4j in main:

Propertyconfigurator. Configure ("log4j. properties ");

 

E). Write a small program and test it. Well, let's take a look at the effect:

[Shenma] cannot find the file exception?

1). It is not recommended to use absolute paths. It is not elegant;

2) Place the log4j file in the bin/directory:

A). In the code, propertyconfigurator. Configure ("Bin/Log4j. properties ");

B) in the code, propertyconfigurator. Configure (Classloader. getsystemresource("Log4j. properties "));

C). Note that the directory must be located in the direct bin directory and not in the deeper bin directory. But is it true that this is for God's horse?

See: http://blog.sina.com.cn/s/blog_3f4755c70100jco1.html

3) Mandatory killer:

Private Static void initlog4j (){
Properties prop = new properties ();

Prop. setproperty ("log4j. rootlogger", "debug, console ");
Prop. setproperty ("log4j. appender. Console", "org. Apache. log4j. leleappender ");
Prop. setproperty ("log4j. appender. Console. layout", "org. Apache. log4j. patternlayout ");
Prop. setproperty ("log4j. appender. console. layout. conversionpattern "," % d {hh: mm: SS, SSS} [% T] %-5 p % c {1}: % m % N ");

Propertyconfigurator. Configure (PROP );
}

 

 

 

[2] log4j format details

 

Log4j. rootlogger = Log Level, appender1, appender2 ,....

• Log Level:All <debug <info <warn <error <fatal <off, Case insensitive
• Note: You must enter one of the appender in the consoleStdoutYou can.
• Note: rootloggerBy defaultEffective
• Note that ifOnly wantOperation, then: log4j. logger.Com. Hutu= Info, stdout, indicates that the log takes effect for package COM.
• Note: in this way, you can differentiate DEV/online, or reduce the performance impact:If (log. isdebugenabled ()){Log. debug ();}

Log4j. appender. appender1 = org. Apache. log4j. Where is the log output?

• Consoleappender(Console)
• Fileappender(File)
• Dailyrollingfileappender(One log file is generated every day)
• Rollingfileappender(A new file is generated when the file size reaches the specified size)
• Writeappender(Send log information to any specified place in stream format)
• Jdbcappender(Save the log information to the database)

Log4j. appender. appender1.file = file directory and file

$ {User. Home}/logs /...

Log4j. appender. appender1.maxfilesize = Maximum File Size

Log4j. appender. appender1.maxbackupindex = number of backup files

• Appender1 is defined in the first line;
• File directory and file, for example,/home/admin/logs/huudan. Log
• Maximum file size, for example, KB
• Number of backup files, for example, 1

Log4j. appender. serverdailyrollingfile. datepattern = Log suffix format

• For example, '.' yyyy-mm-dd

Log4j. appender. appender1.layout = org. Apache. log4j. Log layout format

• Htmllayout (HTML table layout)
• Simplelayout (Level and information string containing log information)
• Ttcclayout (including the log generation time, execution thread, category, and other information)
• Patternlayout (you can flexibly specify the layout format,Common)

Log4j. appender. appender1.layout. conversionpattern = log output format

1. For example, % d-% m % N or % d {yyyy-mm-dd hh: mm: SS} % P [% C] % m % N
2. % CFull name of the class to which the output log information belongs
3. % DThe date or time of the log output time point. The default format is iso8601. You can also specify the format later, for example, % d {YYY-m-dd hh: mm: SS }, output:-22:10:28
4. % FClass Name of the class to which the output log information belongs
5. % LThe location where the log event is generated, that is, the number of lines in the class where the statement that outputs the log information is located
6. % MOutput the specified information in the Code, such as the message in log (Message ).
7. % NReturns a carriage return line break. The windows platform is "RN" and the UNIX platform is "N"
8. % PThe output priority, namely debug, info, warn, error, and fatal. If it is output by calling debug (), it is debug, and so on.
9. % RIt takes several milliseconds to output the log information from application startup to application startup.
10. % TName of the thread that generates the log event
11. See: http://blog.sina.com.cn/s/blog_4e4dd5570100qowy.html

Log4j. appender. serverdailyrollingfile. append = true

• For example, if it is not explained, it is

Summary:

• Logger: completes logging and sets the log information level.
• Appender class: determines the log destination, terminal, DB, Hard Disk
• Layout class: determines the log output style, such as the current thread, row number, and time.