log4j的WriterAppender的使用

这几天做项目，需要做一个类似于控制台的界面，可以将日志回显到一个文本区域里，几经查找，反复测试写了以下测试代码。
这是log4j.properties的配置内容

log4j.rootCategory= ,WriterAppender
log4j.appender.WriterAppender=org.apache.log4j.WriterAppender
log4j.appender.WriterAppender.Threshold=debug
log4j.appender.WriterAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.WriterAppender.layout.ConversionPattern=%d{ISO8601} - %p - %m%n

主程序

import java.io.PipedReader;
import java.io.PipedWriter;
import java.io.Writer;

import org.apache.log4j.Appender;
import org.apache.log4j.Logger;
import org.apache.log4j.WriterAppender;

public class Log4jMain {
    static public Logger logger = Logger.getLogger(Log4jMain.class);

    public static void main(String[] arg) {
       
       
        Logger root = Logger.getRootLogger();
        try {
            Appender appender = root.getAppender("WriterAppender");
            PipedReader reader = new PipedReader();
            Writer writer = new PipedWriter( reader) ;
       
            ((WriterAppender) appender).setWriter(writer);
           
            Thread t = new AaaThread(reader);
            t.start();
            Logger logger = Logger.getLogger(Log4jMain.class);
            logger.error("asdf");
            logger.info("asdf");
            logger.debug("asdf");
            logger.fatal("asdf");
                //hh是一个class，test方法里只有几个logger.info("aaa"),用于测试用，这东西可以去掉
            new HH().test();

        } catch (Exception e) {
        }    }
   
}

       因为log4j提供的是 Writer，所以通过使用PipedWriter连接到PipedReader，并通过一个thread来处理 PipedReader的数据就可以回显了。如果你需要的话可以将下面的 System.out.println(scanner.nextLine());改成你需要显示的地方就行了。

import java.io.PipedReader;
import java.util.Scanner;public class AaaThread extends Thread {
    PipedReader reader;    public AaaThread(PipedReader reader) {
        this.reader = reader;
    }    public void run() {
        Scanner scanner = new Scanner(reader);
        while (scanner.hasNext()) {
            System.out.println(scanner.nextLine());
        }
    }
}