slf4j+log4j的初次使用

关于这两者的组合应用带来的好处，google都有就不说了。

首先说下配置，

工作笔记:在myeclipse 中创建一个java project

创建一个 TestSlf4J 类

package com.joyce.quartz.main;
import org.slf4j.Logger;

import org.slf4j.LoggerFactory;
public class TestSlf4J { 
private static final Logger logger =LoggerFactory.getLogger(TestSlf4J.class); 
public static void main(String[] args) { 
logger.error("Hello world {}"); 
System.out.println("2323");
try {

int i = 1/0;
} catch (Exception e) {
logger.error("出现异常",e);

}
} 
}

同时把slf4j-api-1.1.jar slf4j-log4j12-1.6.1.jar log4j-1.2.16.jar 放入项目里。

再添加一个log4j.properties

# An example log4j configuration file that outputs both to System.out
# and a file named 'test'.

# For the general syntax of property based configuration files see the
# documenation of org.apache.log4j.PropertyConfigurator.

# WARNING: Location information can be useful but is very costly in
# terms of computation.

# The root logger uses the appender called A1.

# The root logger uses the appenders called A1 and A2. Since no level
# is specified, note the empty string between the comma (",") and the
# equals sign ("="), the level of the root logger remains
# untouched. Log4j always initializes the level for the root logger to
# DEBUG. The root logger is the only logger that has a default
# level. Bu default, all other loggers do not have an assigned level,
# such that they inherit their level instead.

log4j.rootLogger=, A1, A2

# A1 is set to be ConsoleAppender sending its output to System.out
log4j.appender.A1=org.apache.log4j.ConsoleAppender

# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout

# The conversion pattern consists of date in ISO8601 format, level,
# thread name, logger name truncated to its rightmost two components
# and left justified to 17 characters, location information consisting
# of file name (padded to 13 characters) and line number, nested
# diagnostic context, the and the application supplied message

log4j.appender.A1.layout.ConversionPattern=%d %-5p [%t] %-17c{2} (%13F:%L) %3x - %m%n

# Appender A2 writes to the file "test".
log4j.appender.A2=org.apache.log4j.FileAppender
log4j.appender.A2.File=e:/test.log

# Truncate 'test' if it aleady exists.
log4j.appender.A2.Append=false

# Appender A2 uses the PatternLayout.
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%-5r %-5p [%t] %c{2} %d{yyyy-MM-dd HH:mm:ss,SSS} [%c]-[%p]%m%n

# In this example, we are not interested in INNER loop or SWAP
# messages. You might try to set INNER and SWAP to DEBUG for more
# verbose output.

log4j.logger.org.apache.log4j.examples.SortAlgo.INNER=INFO
log4j.logger.org.apache.log4j.examples.SortAlgo.SWAP=INFO

项目结构如图：

最后运行TestSlf4J类在e盘就生成了一个test.log文件生成内容如下：

注意：

slf4j-log4j12-1.6.1.jar是连接包，我们在java里直接用slf4j创建的log,如果没有这个连接包，是创建不出log的

还要注意的是，在没加这个连接包的时候，

会报

SLF4J: Failed to load class “org.slf4j.impl.StaticLoggerBinder”

有解决办法是说：下载slf4j-nop.jar，添加到路径中，就解决问题了

但我这边是不能下这个包，加了会报错

所以。总的加那三个包就可以了

today lazy . tomorrow die .