Java Web动态配置log4j

导入log4j的jar包，

在web.xml中做如下配置

　　<!-- Log4j Configuration -->

    <context-param>

        <param-name>webAppRootKey</param-name>

        <param-value>myapplication.root</param-value>

    </context-param>

    <context-param>

        <param-name>log4jConfigLocation</param-name>

        <param-value>/WEB-INF/log4j.properties</param-value>

    </context-param>

    <context-param>

        <param-name>log4jRefreshInterval</param-name>

        <param-value>60000</param-value><!-- 重新加载log4j配置的间隔时间 ms -->

    </context-param>

在WEB-INF下建立文件log4j.properties

内容如下

log4j.rootLogger=INFO, stdout, logfile



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

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

log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n



log4j.appender.logfile=org.apache.log4j.RollingFileAppender

log4j.appender.logfile.File=${user.home}/myapplication.log

log4j.appender.logfile.MaxFileSize=512KB

log4j.appender.logfile.layout=org.apache.log4j.PatternLayout

log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

可根据不同的需求进行不同的配置。

在web页面上做个选择logging level的页面，选择logging level，传入servlet，

　　
　　//查询logging level，并传到web页面
　　@RequestMapping(value="/logging_view", method = RequestMethod.GET)

    public String toLoggingView(HttpServletRequest request,Model model){

        Properties props = new Properties();

        try {
　　　　　　　//读取log4j.properties文件的内容

            String path = SystemController.class.getClassLoader().getResource("").toURI().getPath();

            InputStream in = new BufferedInputStream(new FileInputStream(

                    path+"../log4j.properties"));//这个是log4j.properties的文件路径，根据自己的servlet的path自行配置

            props.load(in);

            String value = props.getProperty("log4j.rootLogger");

            logger.debug("log4j.rootLogger键的值是："+ value);

            model.addAttribute("rootLogger", value);

            in.close();

        } catch (URISyntaxException e) {

            logger.error("SystemController : logging_view : URISyntaxException:"+e);

        } catch (FileNotFoundException e) {

            logger.error("SystemController : logging_view : FileNotFoundException:"+e);

        } catch (IOException e) {

            logger.error("SystemController : logging_view : IOException:"+e);

        }

        return SessionHandler.verifySession(request, "logging_view");

    }

    //获取web页面传的数据，设置logging level

    @RequestMapping(value="/setLoggingLevel", method = RequestMethod.POST)

    public String setLoggingLevel(@RequestParam String rootLogger, @RequestParam String loggerLevel,

            HttpServletRequest request, Model model){

        RequestContext requestContext = new RequestContext(request);

        String[] loggers = rootLogger.split(",");

        loggers[0] = loggerLevel;

        String logging = "";

        for(int i = 0; i < loggers.length; i++){

            logging += loggers[i]+",";

        }

        logging = logging.substring(0, logging.length()-1);

        Properties props = new Properties();

        try {
　　　　　　　//将logging level写入log4j.properties文件

            String path = SystemController.class.getClassLoader().getResource("").toURI().getPath()+"../log4j.properties";

            InputStream in = new BufferedInputStream(new FileInputStream(

                    path));

            props.load(in);

            OutputStream fos = new FileOutputStream(path);

            props.setProperty("log4j.rootLogger", logging);

            props.store(fos,"last update");

            String value = props.getProperty("log4j.rootLogger");

            logger.debug(value);

            //关闭文件

            in.close();

            fos.close();

            List<String> list = new ArrayList<String>();

            list.add(requestContext.getMessage("logging.level"));

            if(value.split(",")[0].equals(loggerLevel)){

                model.addAttribute("msg", requestContext.getMessage("edit.success",list));

            }else{

                model.addAttribute("msg", requestContext.getMessage("edit.failed",list));

            }

        } catch (URISyntaxException e) {

            logger.error("SystemController : logging_view : URISyntaxException:"+e);

        } catch (FileNotFoundException e) {

            logger.error("SystemController : logging_view : FileNotFoundException:"+e);

        } catch (IOException e) {

            logger.error("SystemController : logging_view : IOException:"+e);

        }

        return "msg";

    }

这样就完成了，log4j的其他配置，一样按照上面的方法做就行。