log4j的使用

Log4j是Apache的一个开源项目，通过使用Log4j，我们可以控制日志信息输送的目的地是控制台、文件、GUI组件，甚至是套接口服务器、NT的事件记录器、UNIX Syslog 守护进程等；我们也可以控制每一条日志的输出格式；通过定义每一条日志信息的级别，我们能够更加细致地控制日志的生成过程。最令人感兴趣的就是，这些可以通过一个配置文件来灵活地进行配置，而不需要修改应用的代码。

配置

1.在maven中加入依赖包,slf4j-log4j12、log4j

 1 <dependency>
 2    <groupId>org.slf4j</groupId>
 3    <artifactId>slf4j-log4j12</artifactId>
 4    <version>${slf4j.version}</version>
 5 </dependency>
 6 <dependency>
 7    <groupId>log4j</groupId>
 8    <artifactId>log4j</artifactId>
 9    <version>${log4j.version}</version>
10 </dependency>
11 <dependency>
12 
13 
14 <log4j.version>1.2.16</log4j.version>
15 <slf4j.version>1.6.1</slf4j.version>

View Code

2.在CLASSPATH下建立log4j.properties。内容如下(数字为行号)：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
 4 
 5 <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
 6     <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
 7         <param name="Encoding" value="UTF-8" />
 8         <layout class="org.apache.log4j.PatternLayout">
 9             <param name="ConversionPattern" value="%c - %m%n" />
10         </layout>
11     </appender>
12 
13     <appender name="fileError" class="org.apache.log4j.DailyRollingFileAppender">
14         <param name="File" value="../logs/scm.log" />
15         <param name="Encoding" value="UTF-8" />
16         <layout class="org.apache.log4j.PatternLayout">
17             <param name="ConversionPattern" value="%d{yy-MM-dd HH:mm:ss} %m %n" />
18         </layout>
19     </appender>
20 <!-- 开发环境 -->    
21     <logger name="com.gta.scm" additivity="true">
22         <level value="debug" />
23         <appender-ref ref="stdout" />
24         <appender-ref ref="fileError" />
25     </logger>
26     <logger name="org.springframework" additivity="true">
27         <level value="error" />
28         <appender-ref ref="stdout" />
29         <appender-ref ref="fileError" />
30     </logger>
31      <logger name="org.mybatis" additivity="true"> 
32         <level value="error" />
33         <appender-ref ref="stdout" />
34         <appender-ref ref="fileError" />
35      </logger>
36 
37     <logger name="java.sql.Connection" additivity="true">
38         <level value="debug" />
39         <appender-ref ref="stdout" />
40         <appender-ref ref="fileError" />
41     </logger>
42 
43     <logger name="java.sql.Statement" additivity="true">
44         <level value="debug" />
45         <appender-ref ref="stdout" />
46         <appender-ref ref="fileError" />
47     </logger>
48 
49     <logger name="java.sql.PreparedStatement" additivity="true">
50         <level value="debug" />
51         <appender-ref ref="stdout" />
52         <appender-ref ref="fileError" />
53     </logger>
54     
55     <logger name="java.sql.ResultSet" additivity="true"> 
56          <level value="error" />
57          <appender-ref ref="stdout" />
58      </logger>     
59      <logger name="org.apache.ibatis.logging.jdbc.ConnectionLogger" additivity="true"> 
60          <level value="debug" />
61          <appender-ref ref="stdout" />
62      </logger> 
63 <!-- 生产环境 -->
64      <!-- <root>
65         <level value="error" />
66         <appender-ref ref="fileError" />
67     </root>  -->
68 </log4j:configuration>

View Code

3.在要输出日志的类中加入相关语句：

 1 public class SimpleLogger {
 2 
 3     private Logger simpleLogger = null;
 4 
 5     static class SingletonHolder {
 6         static SimpleLogger instance = new SimpleLogger();
 7     }
 8 
 9     public static SimpleLogger getLogger() {
10         return SingletonHolder.instance;
11     }
12 
13     public static SimpleLogger getLogger(Class<?> clazz) {
14         return new SimpleLogger(clazz);
15     }
16 
17     private SimpleLogger() {
18         simpleLogger = null;
19         simpleLogger = LoggerFactory.getLogger("pango logger");
20     }
21 
22     private SimpleLogger(Class<?> clazz) {
23         simpleLogger = LoggerFactory.getLogger(clazz);
24     }
25 
26     public void error(String message) {
27         simpleLogger.error(message);
28     }
29 
30     public void error(String message, Throwable t) {
31         simpleLogger.error(message, t);
32     }
33 
34     public void error(String format, Object arg1, Object arg2) {
35         simpleLogger.error(format, arg1, arg2);
36     }
37 
38     public void error(String format, Object... args) {
39         simpleLogger.error(format, args);
40     }
41 
42     public void debug(String message) {
43         simpleLogger.debug(message);
44     }
45 
46     public void debug(String message, Throwable t) {
47         simpleLogger.debug(message, t);
48     }
49 
50     public void warn(String message) {
51         simpleLogger.warn(message);
52     }
53 
54     public void warn(String message, Throwable t) {
55         simpleLogger.warn(message, t);
56     }
57     
58     public void warn(String format, Object... args) {
59         simpleLogger.warn(format, args);
60     }
61 
62     public void info(String message) {
63         simpleLogger.info(message);
64     }
65 
66     public void info(String message, Throwable t) {
67         simpleLogger.info(message, t);
68     }
69 
70     public boolean isDebugEnabled() {
71         return simpleLogger.isDebugEnabled();
72     }
73 }

View Code

4.在项目中的使用

private static SimpleLogger logger = SimpleLogger.getLogger(SpringContextHelper.class);

或者直接用org.slf4j.LoggerFactory

private static final Logger logger = LoggerFactory.getLogger(SalesManageController.class);

logger.error(e.getMessage(), e);