随笔 - 166  文章 - 4  评论 - 59  阅读 - 29万

[Log4J]一个只打Console并且设有最高级别的Appender

/*
 * Copyright 1999-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
 
 
import java.io.IOException;
import java.io.OutputStream;
 
import org.apache.log4j.Layout;
import org.apache.log4j.Level;
import org.apache.log4j.WriterAppender;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
 
/**
 * ConsoleAppender appends log events to <code>System.out</code> or
 * <code>System.err</code> using a layout specified by the user. The default
 * target is <code>System.out</code>.
 *
 * @author Ceki Gülcü
 * @author Curt Arnold
 * @since 1.1
 */
public class MyAppender extends WriterAppender {
 
    public static final String SYSTEM_OUT = "System.out";
    public static final String SYSTEM_ERR = "System.err";
 
    protected String target = SYSTEM_OUT;
 
    /**
     * Determines if the appender honors reassignments of System.out or
     * System.err made after configuration.
     */
    private boolean follow = false;
 
    /**
     * Constructs an unconfigured appender.
     */
    public MyAppender() {
    }
 
    /**
     * Creates a configured appender.
     *
     * @param layout
     *            layout, may not be null.
     */
    public MyAppender(Layout layout) {
        this(layout, SYSTEM_OUT);
    }
 
    /**
     * Creates a configured appender.
     *
     * @param layout
     *            layout, may not be null.
     * @param targetStr
     *            target, either "System.err" or "System.out".
     */
    public MyAppender(Layout layout, String target) {
        setLayout(layout);
        setTarget(target);
        activateOptions();
    }
 
    /**
     * Sets the value of the <b>Target</b> option. Recognized values are
     * "System.out" and "System.err". Any other value will be ignored.
     * */
    public void setTarget(String value) {
        String v = value.trim();
 
        if (SYSTEM_OUT.equalsIgnoreCase(v)) {
            target = SYSTEM_OUT;
        } else if (SYSTEM_ERR.equalsIgnoreCase(v)) {
            target = SYSTEM_ERR;
        } else {
            targetWarn(value);
        }
    }
 
    /**
     * Returns the current value of the <b>Target</b> property. The default
     * value of the option is "System.out".
     *
     * See also {@link #setTarget}.
     * */
    public String getTarget() {
        return target;
    }
 
    /**
     * Sets whether the appender honors reassignments of System.out or
     * System.err made after configuration.
     *
     * @param newValue
     *            if true, appender will use value of System.out or System.err
     *            in force at the time when logging events are appended.
     * @since 1.2.13
     */
    public final void setFollow(final boolean newValue) {
        follow = newValue;
    }
 
    /**
     * Gets whether the appender honors reassignments of System.out or
     * System.err made after configuration.
     *
     * @return true if appender will use value of System.out or System.err in
     *         force at the time when logging events are appended.
     * @since 1.2.13
     */
    public final boolean getFollow() {
        return follow;
    }
 
    @Override
    public void append(LoggingEvent event) {
 
        // Reminder: the nesting of calls is:
        //
        // doAppend()
        // - check threshold
        // - filter
        // - append();
        // - checkEntryConditions();
        // - subAppend();
        //[yangyh]
        if (event.getLevel().isGreaterOrEqual(Level.WARN)) {
            return;
        }
        if (!checkEntryConditions()) {
            return;
        }
        subAppend(event);
    }
 
    void targetWarn(String val) {
        LogLog.warn("[" + val + "] should be System.out or System.err.");
        LogLog.warn("Using previously set target, System.out by default.");
    }
 
    /**
     * Prepares the appender for use.
     */
    @Override
    public void activateOptions() {
        if (follow) {
            if (target.equals(SYSTEM_ERR)) {
                setWriter(createWriter(new SystemErrStream()));
            } else {
                setWriter(createWriter(new SystemOutStream()));
            }
        } else {
            if (target.equals(SYSTEM_ERR)) {
                setWriter(createWriter(System.err));
            } else {
                setWriter(createWriter(System.out));
            }
        }
        super.activateOptions();
    }
 
    /**
     * {@inheritDoc}
     */
    @Override
    protected final void closeWriter() {
        if (follow) {
            super.closeWriter();
        }
    }
 
    /**
     * An implementation of OutputStream that redirects to the current
     * System.err.
     *
     */
    private static class SystemErrStream extends OutputStream {
        public SystemErrStream() {
        }
 
        @Override
        public void close() {
        }
 
        @Override
        public void flush() {
            System.err.flush();
        }
 
        @Override
        public void write(final byte[] b) throws IOException {
            System.err.write(b);
        }
 
        @Override
        public void write(final byte[] b, final int off, final int len) throws IOException {
            System.err.write(b, off, len);
        }
 
        @Override
        public void write(final int b) throws IOException {
            System.err.write(b);
        }
    }
 
    /**
     * An implementation of OutputStream that redirects to the current
     * System.out.
     *
     */
    private static class SystemOutStream extends OutputStream {
        public SystemOutStream() {
        }
 
        @Override
        public void close() {
        }
 
        @Override
        public void flush() {
            System.out.flush();
        }
 
        @Override
        public void write(final byte[] b) throws IOException {
            System.out.write(b);
        }
 
        @Override
        public void write(final byte[] b, final int off, final int len) throws IOException {
            System.out.write(b, off, len);
        }
 
        @Override
        public void write(final int b) throws IOException {
            System.out.write(b);
        }
    }
 
}

  log4j.properties:

### set log levels ###
log4j.rootLogger = debug , stderr, D, A1

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{ABSOLUTE} %5p %c{1}:%L - %m%n

log4j.appender.stderr = org.apache.log4j.ConsoleAppender
log4j.appender.stderr.Target = System.err
log4j.appender.stderr.Threshold = WARN
log4j.appender.stderr.layout = org.apache.log4j.PatternLayout
log4j.appender.stderr.layout.ConversionPattern = %d{ABSOLUTE} %5p %c{1}:%L - %m%n


log4j.appender.A1 = com.baidu.tv.video.fetcher.log.MyAppender
log4j.appender.A1.Target = System.out
log4j.appender.A1.Threshold = DEBUG
log4j.appender.A1.layout = org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern = %d{ABSOLUTE} %5p %c{1}:%L - %m%n

log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = logs/error.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = WARN
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n

貌似现在的Appender只有最低级别:Threshold<br>这里重写了WriterAppander的append方法
posted on   yangyh  阅读(1843)  评论(0编辑  收藏  举报
编辑推荐:
· .NET Core内存结构体系(Windows环境)底层原理浅谈
· C# 深度学习:对抗生成网络(GAN)训练头像生成模型
· .NET 适配 HarmonyOS 进展
· .NET 进程 stackoverflow异常后,还可以接收 TCP 连接请求吗?
· SQL Server统计信息更新会被阻塞或引起会话阻塞吗?
阅读排行:
· 传国玉玺易主,ai.com竟然跳转到国产AI
· 本地部署 DeepSeek:小白也能轻松搞定!
· 自己如何在本地电脑从零搭建DeepSeek!手把手教学,快来看看! (建议收藏)
· 我们是如何解决abp身上的几个痛点
· 普通人也能轻松掌握的20个DeepSeek高频提示词(2025版)
< 2013年5月 >
28 29 30 1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31 1
2 3 4 5 6 7 8

点击右上角即可分享
微信分享提示