日志记录不显示

Question

} catch(Exception e) {
      System.out.println("This gets printed in Netbeans tab");
      LOG.log(Level.SEVERE, "This doesnt");
}

我怀疑这可能是我包含的一个库，它正在扰乱我的日志。这有可能吗？librray可以改变我的日志显示方式吗？既然我有点迷路了，我该怎么调查呢？

Answer 1

我怀疑这可能是我包含的一个库，它正在扰乱我的日志。这有可能吗？

是的。JUL到SLF4J的桥可以从JUL根记录器中删除控制台处理程序。有些库调用logmanager.reset，这可以删除和关闭所有处理程序。

库可以更改日志的显示方式吗？

import java.io.File;
import java.io.IOException;
import java.io.PrintStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Enumeration;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.Logger;

public class DebugLogging {

    private static final Logger log = Logger.getLogger("test");

    public static void main(String[] a) {
        log.log(Level.FINEST, "Finest");
        log.log(Level.FINER, "FINER");
        log.log(Level.FINE, "FINE");
        log.log(Level.CONFIG, "CONFIG");
        log.log(Level.INFO, "INFO");
        log.log(Level.WARNING, "WARNING");
        log.log(Level.SEVERE, "SEVERE");
        log.finest("Finest Log");
        log.finer("Finer Log");
        log.fine("Fine Log");
        log.config("Config Log");
        log.info("Info Log");
        log.warning("Warning Log");
        log.severe("Severe Log");
        printConfig(System.err);
    }

    private static void printConfig(PrintStream ps) {
        String cname = System.getProperty("java.util.logging.config.class");
        if (cname != null) {
            try {
                ClassLoader sys = ClassLoader.getSystemClassLoader();
                Class<?> c = Class.forName(cname, false, sys);
                ps.println(sys.getClass().getName() +" found log configuration class " + c.getName());
            } catch (LinkageError | ClassNotFoundException | RuntimeException cnfe) {
                ps.println("Unable to load " + cname);
                cnfe.printStackTrace(ps);
            }
        } else {
            ps.println("java.util.logging.config.class was null");
        }
        
        String file = System.getProperty("java.util.logging.config.file");
        if (file != null) {
           ps.println("java.util.logging.config.file=" + file);
           try {
               ps.println("CanonicalPath=" + new File(file).getCanonicalPath());
           } catch (RuntimeException | IOException ioe) {
               ps.println("Unable to resolve path for " + file);
               ioe.printStackTrace(ps);
           }

           try {
               Path p = Paths.get(file);
               if (Files.isReadable(p)) {
                   ps.println(file + " is readable and has size " + Files.size(p));
               } else {
                   if (Files.exists(p)) {
                       ps.println(file + " exists for " + System.getProperty("user.name") + " but is not readable.");
                   } else {
                       ps.println(file + " doesn't exist for " + System.getProperty("user.name"));
                   }
               }
           } catch (RuntimeException | IOException ioe) {
               ps.println("Unable to read " + file);
               ioe.printStackTrace(ps);
           }
        } else {
            ps.println("java.util.logging.config.file was null");
        }

        LogManager lm = LogManager.getLogManager();
        ps.append("LogManager=").println(lm.getClass().getName());
        synchronized (lm) {
            Enumeration<String> e = lm.getLoggerNames();
            while (e.hasMoreElements()) {
                Logger l = lm.getLogger(e.nextElement());
                if (l != null) {
                    print(l, ps);
                }
            }
        }
    }

    private static void print(Logger l, PrintStream ps) {
        String scn = l.getClass().getSimpleName();
        ps.append("scn=").append(scn).append(", n=").append(l.getName())
                .append(", uph=").append(String.valueOf(l.getUseParentHandlers()))
                .append(", l=").append(String.valueOf(l.getLevel()))
                .append(", fl=").println(l.getFilter());
        for (Handler h : l.getHandlers()) {
            ps.append("\t").append(l.getName()).append("->")
                    .append(h.getClass().getName()).append(", h=")
                    .append(String.valueOf(h.getLevel())).append(", fl=")
                    .append(String.valueOf(h.getFilter())).println();
        }
    }
}