java 将 javax.net.debug 捕获到文件
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Capture javax.net.debug to file
提问by Loomer
I need to save the javax.net.debug=all output that is created to a file. I'm using log4j and I tried creating a logging proxy as in the code example below; however, it is not picking up the info. I am not sure where the javax.net.debug is being printed to. I tried capturing system.out and system.err this way but neither worked. Thanks for your help.
我需要将创建的 javax.net.debug=all 输出保存到文件中。我正在使用 log4j，并尝试创建一个日志代理，如下面的代码示例所示；但是，它没有获取信息。我不确定 javax.net.debug 被打印到哪里。我尝试以这种方式捕获 system.out 和 system.err，但都没有奏效。谢谢你的帮助。
public class StdOutErrLog {
private static final Logger logger = Logger.getLogger(StdOutErrLog.class);
public static void tieSystemOutAndErrToLog() {
System.setOut(createLoggingProxy(System.out));
System.setErr(createLoggingProxy(System.err));
}
public static PrintStream createLoggingProxy(final PrintStream realPrintStream) {
return new PrintStream(realPrintStream) {
public void print(final String string) {
realPrintStream.print(string);
logger.info(string);
}
};
}
}
采纳答案by mtraut
Maybe the subsystem makes its copy of the values and you are too late when switching. Try doing this first in your main.
也许子系统会复制这些值，而您在切换时为时已晚。尝试首先在您的主要内容中执行此操作。
EDIT
编辑
OK - i missed completely your idiom. I think you should not use this inner class. You should define a PrintStream instance on an OutputStream that creates a new log entry upon every "\n". The way you do it now misses a lot of possibilities to "print around" your instance.
好的 - 我完全错过了你的成语。我认为你不应该使用这个内部类。您应该在 OutputStream 上定义一个 PrintStream 实例，该实例在每个“\n”上创建一个新的日志条目。你现在这样做的方式错过了很多“打印”你的实例的可能性。
package de.mit.stackoverflow;
import java.io.IOException;
import java.io.OutputStream;
public class LogOutputStream extends OutputStream {
private StringBuilder sb = new StringBuilder();
@Override
public void write(int b) throws IOException {
if (b == '\n') {
log(sb.toString());
sb.setLength(0);
} else {
sb.append((char) b);
}
}
}
and then do
然后做
OutputStream os = new LogOutputStream();
PrintStream ps = new PrintStream(os);
System.setOut(ps);
You maybe still want to include a reference to the previous stream - left as excercise :-)
您可能仍然希望包含对上一个流的引用 - 留作练习 :-)
回答by Matt Solnit
This is a long shot, but it's possible that overriding print(String)is not enough. For example, there is also print(Object), etc., not to mention the various append()and format()methods.
这是一个远景，但覆盖可能print(String)还不够。比如还有print(Object)，等等，更不用说各种append()和format()方法了。
回答by Mat B.
You need to have log4j.properties file in class-path (/WEB-INF/classes/) with following content:
您需要在类路径 (/WEB-INF/classes/) 中有 log4j.properties 文件，其中包含以下内容：
log4j.properties file
log4j.properties 文件
datestamp=yyyy-MM-dd/HH:mm:ss.SSS/zzz
roll.pattern.hourly=.MM-dd-yyyy.HH
roll.pattern.daily=.MM-dd-yyyy
log4j.rootLogger=INFO, Console
log4j.logger=INFO, Console
log4j.appender.Console=org.apache.log4j.DailyRollingFileAppender
log4j.appender.Console.DatePattern=${roll.pattern.daily}
log4j.appender.Console.file=${catalina.home}/logs/Console.log
log4j.appender.Console.MaxFileSize=800KB
log4j.appender.Console.MaxBackupIndex=5
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=%d{${datestamp}} [%t] %-5p %m%n
log4j.appender.custom=org.apache.log4j.DailyRollingFileAppender
log4j.appender.custom.DatePattern=${roll.pattern.daily}
log4j.appender.custom.File=${catalina.home}/logs/custom.log
log4j.appender.custom.MaxFileSize=800KB
log4j.appender.custom.MaxBackupIndex=5
log4j.appender.custom.layout=org.apache.log4j.PatternLayout
log4j.appender.custom.layout.ConversionPattern=%d{${datestamp}} [%t] %-5p %m%n
log4j.logger.net.javax=DEBUG, custom
This will write your log entries into tomcat home directory /logs/custom.log
这会将您的日志条目写入 tomcat 主目录 /logs/custom.log
Hope this will help you.
希望这会帮助你。
