How can i use 'log' inside a src/groovy/ c

问题:

I'm encountering this error:

groovy.lang.MissingPropertyException: No such property: log for class: org.utils.MyClass

Here's the content of the class:

package org.utils

class MyClass {
    int organizationCount = 0

    public int getOrganizationCount(){
        log.debug "There are ${organizationCount} organization(s) found."
        return organizationCount
    }

}

Do i need to add an import statement? What do i need to add? Note that the class is located in src/groovy/org/utils. I know that the 'log' variable is accessible in controllers, services, etc. Not sure in 'src' classes.

Thanks.

回答1:

In Groovy 1.8, you may also annotate the class with @Log (for java.util.logging) or @Log4j (for log4j) and it will "magically" have a log property. See http://docs.codehaus.org/display/GROOVY/Groovy+1.8+release+notes#Groovy1.8releasenotes-@Log for details.

PS.: If you use java.util.logging the log.debugcall will still fail because there's no debug method.

回答2:

In grails 3, the default logging system is logback. Simply adding the @Slf4j annotation to your src/groovy class will take care of things.

import groovy.util.logging.Slf4j

@Slf4j
class MyUtil {

回答3:

The log variable is injected by grails and thus only available in the grails-specific classes like controllers, services, etc. - and I don't think you can "import" that in any way.

Outside these classes, you'll just have to use log4j "regularly", i.e.

Logger.getLogger(MyClass.class).debug()

回答4:

Log4j is one of the best logging for groovy

import groovy.util.logging.Log4j

@Log4j
public class MyClass{
//Use for logger check
public static void myMethod(){
    //log.error(null, "This is the log message", throwable)

    //log.error(null, "This is the log message", throwable)

    //log.info("This is the message for info")

    //log.debugg("This is the message for debugging")
}
}

Log4j.properties

# Define the root logger with appender file
log =folderpath
log4j.rootLogger=INFO, R, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# %d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%C:%L [%t]  - %m%n

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=${log}/filename.log

log4j.appender.R.MaxFileSize=2048KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern="%d %5p %c{1}:%L - %m%n"
# %d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%C:%L [%t]  - %m%n

# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Hope it will help you....

回答5:

Well I have done this in grails 3.1.8 which uses Logback.

import org.apache.commons.logging.LogFactory

public class MyClass{

   static final LOG = LogFactory.getLog(this)

   def function(){
     LOG.debug "Debug message"
   }

   static staticFunction(){
     LOG.debug "Another debug message"
   }
}