如何为log4j设置单独的日志记录流？

Question

说我有一个这样的班级：

public class MyClass
{

    private Logger log = LoggerFactory.getLogger(MyClass.class); //org.slf4j.LoggerFactory

    public void foo(Params p)
    {
         log.info("Foo params: " + p);
         long t1 = System.currentTimeMillis();

         Result r = someMethod(p);

         long t2 = System.currentTimeMillis();
         log.info("Foo result: " + r)
         log.info("Foo time taken: + (t2-t1)/1000); 
    }

}

现在，当涉及到打印此信息时，我希望能够打开和关闭不同类型的信息（参数，结果，花费的时间）。

使用日志记录级别进行区分的问题在于，更精细的粒度级别还包含了更粗糙的级别。

如何轻松设置？

Answer 1

您可以通过创建自定义日志记录类来设置不同的日志记录行为。

这是我的解决方案：

public abstract class AbstractLogger {

    protected Logger log;
    protected Class callingClass;
    public AbstractLogger(Class c)
    {
        this.log = LoggerFactory.getLogger(this.getClass());
        this.callingClass = c;
    }

    public void log(String s)
    {
        log.debug(this.callingClass + " :" + s);
    }

}

public class LoggerOne extends AbstractLogger {

    public LoggerOne(Class c) {
        super(c);           
    }

}

public class LoggerTwo extends AbstractLogger {

    public LoggerTwo(Class c) {
        super(c);           
    }

}

public class LoggerThree extends AbstractLogger {

    public LoggerThree(Class c) {
        super(c);           
    }    
}

在Log4j.properties中设置

#Define custom levels by package
#set to ERROR to turn them off
log4j.logger.org.myproject.loggers.LoggerOne=ERROR
log4j.logger.org.myproject.loggers.LoggerTwo=DEBUG
log4j.logger.org.myproject.loggers.LoggerThree=DEBUG

使用这些记录器时：

要使用这些记录器：

 public class MyMain {


    // private Logger log = LoggerFactory.getLogger(MyMain.class);

     private AbstractLogger l1= new LoggerOne(this.getClass());
     private AbstractLogger l2= new LoggerTwo(this.getClass());
     private AbstractLogger l3= new LoggerThree(this.getClass());


    public void run()
    {

            l1.log("log 1");

             long t1 = System.currentTimeMillis();

             try {
                    Thread.sleep(1000);                 //1000 milliseconds is one second.
                } catch(InterruptedException ex) {
                    Thread.currentThread().interrupt();
                }

             long t2 = System.currentTimeMillis();
             l2.log("log 2");
             l3.log("Foo time taken:" + (t2-t1)/1000);

    }

    public static void main(String[] args) {

        MyMain me = new MyMain();
        me.run();

    }

}

日志输出：

12:27:29 DEBUG LoggerTwo:18 - class maventestspace.MyMain :log 2
12:27:29 DEBUG LoggerThree:18 - class maventestspace.MyMain :Foo time taken:1

请注意，LoggerOne无法打印，因为在属性文件中将其设置为ERROR。

要重定向这些单独的日志文件，您需要设置新的附加程序和记录器。

log4j.logger.org.myproject.loggers.LoggerOne=DEBUG, file1, stdout
log4j.logger.org.myproject.loggers.LoggerTwo=DEBUG, file2, stdout
log4j.logger.org.myproject.loggers.LoggerThree=DEBUG, file3, stdout


# Direct log messages to a log file
log4j.appender.file1=org.apache.log4j.RollingFileAppender
#log4j.appender.TextProcessor.Threshold=debug
log4j.appender.file1.File=E:\\logs\\log1.txt
log4j.appender.file1.MaxFileSize=10MB
log4j.appender.file1.MaxBackupIndex=1
log4j.appender.file1.layout=org.apache.log4j.PatternLayout
log4j.appender.file1.layout.ConversionPattern=%d{HH:mm:ss} %-5p %c{1}:%L - %m%n




# Direct log messages to a log file
log4j.appender.file2=org.apache.log4j.RollingFileAppender
#log4j.appender.TextProcessor.Threshold=debug
log4j.appender.file2.File=E:\\logs\\log2.txt
log4j.appender.file2.MaxFileSize=10MB
log4j.appender.file2.MaxBackupIndex=1
log4j.appender.file2.layout=org.apache.log4j.PatternLayout
log4j.appender.file2.layout.ConversionPattern=%d{HH:mm:ss} %-5p %c{1}:%L - %m%n



# Direct log messages to a log file
log4j.appender.file3=org.apache.log4j.RollingFileAppender
#log4j.appender.TextProcessor.Threshold=debug
log4j.appender.file3.File=E:\\logs\\log3.txt
log4j.appender.file3.MaxFileSize=10MB
log4j.appender.file3.MaxBackupIndex=1
log4j.appender.file3.layout=org.apache.log4j.PatternLayout
log4j.appender.file3.layout.ConversionPattern=%d{HH:mm:ss} %-5p %c{1}:%L - %m%n