Java 如何从日志(log)行中删除包名称

发布于01月08日

Java util日志(log)记录使用以下输出行格式:

java.util.logging.SimpleFormatter.format = %4$s %2$s %n

这将提供以下输出，其中第一个main是一个package名称，而最后一个main是一个method名称:

Info Main.MySuperPuperClassName Main

如何消除这里的包名？因此，生成的日志(log)行将如下所示:

信息MySuperPuperClassName Main

这样做的目的是不在日志(log)行中输出包名称.

推荐答案

我很确定你不能单独使用日志(log)属性来完成这个任务. 但是，您可以编写自己的Formatter类:

import java.time.ZonedDateTime;
import java.time.ZoneId;

import java.io.StringWriter;
import java.io.PrintWriter;

import java.util.IllegalFormatException;

import java.util.logging.LogManager;
import java.util.logging.LogRecord;
import java.util.logging.SimpleFormatter;

public class NoPackageFormatter
extends SimpleFormatter {
    private static final String FORMAT_PROPERTY =
        "java.util.logging.SimpleFormatter.format";

    private static final String DEFAULT_FORMAT = "%4$s %2$s%6$s%n";
    // Java SE's default for US English locale
    //private static final String DEFAULT_FORMAT =
    //    "%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s%n%4$s: %5$s%6$s%n";

    private static final ZoneId ZONE = ZoneId.systemDefault();

    private static String stripPackage(String name) {
        return name.substring(name.lastIndexOf('.') + 1);
    }

    @Override
    public String format(LogRecord record) {
        String formatString = System.getProperty(FORMAT_PROPERTY);
        if (formatString == null) {
            formatString =
                LogManager.getLogManager().getProperty(FORMAT_PROPERTY);
        }
        if (formatString == null) {
            formatString = DEFAULT_FORMAT;
        }

        String name = record.getLoggerName();
        name = stripPackage(name);

        String sourceClass = record.getSourceClassName();
        String sourceMethod = record.getSourceMethodName();
        String source = sourceClass != null && sourceMethod != null ?
            stripPackage(sourceClass) + ' ' + sourceMethod : name;

        String stackTrace = "";
        if (record.getThrown() != null) {
            StringWriter writer = new StringWriter();
            record.getThrown().printStackTrace(new PrintWriter(writer));
            stackTrace = System.lineSeparator() + writer;
        }

        Object[] args = {
            record.getInstant().atZone(ZONE),
            source,
            name,
            record.getLevel().getLocalizedName(),
            formatMessage(record),
            stackTrace
        };

        try {
            return String.format(formatString, args);
        } catch (IllegalFormatException e) {
            return String.format(DEFAULT_FORMAT, args);
        }
    }
}

要使用它，您可以在日志(log)属性中引用它:

java.util.logging.ConsoleHandler.formatter: com.example.NoPackageFormatter
java.util.logging.FileHandler.formatter:    com.example.NoPackageFormatter
java.util.logging.SocketHandler.formatter:  com.example.NoPackageFormatter

或者，您可以通过编程方式设置它:

private static final Logger logger;

static {
    logger = Logger.getLogger(MyApplication.class.getName());

    Formatter formatter = new NoPackageFormatter();

    for (Logger l = logger; l != null; l = l.getParent()) {
        for (Handler handler : l.getHandlers()) {
            handler.setFormatter(formatter);
        }
    }
}