log4j 相关配制说明：

自己定义异常

package org.rui.ExceptionTest;public class ExtraFeature {	//-------使用------	public static void f()throws MyException	{	 System.out.println("MyException from f()");	 throw new MyException();	}		public static void l()throws MyException	{	 System.out.println("MyException from l()");	 throw new MyException("Originated in l()");	}			public static void r()throws MyException	{	 System.out.println("MyException from r()");	 throw new MyException("originated(起源) in r()");	}		//-------main---------	public static void main(String[] args) 	{		try {			f();		} catch (MyException e) {			e.printStackTrace(System.out);		}		try {			l();		} catch (MyException e) {			e.printStackTrace(System.err);		}		try {			r();		} catch (MyException e) {			e.printStackTrace(System.out);			System.out.println("getLocalizedMessage: "+e.getLocalizedMessage());		    //栈轨迹			for(StackTraceElement ste:e.getStackTrace())				System.out.println("methodName:"+ste.getMethodName());		}	}}//自己定义异常---class MyException  extends Exception{	private int x;	public MyException(){}	public MyException(String msg){super(msg);}		public MyException(String msg,int x)	{		super(msg);		this.x=x;	}		public int val(){return x;}	public String getMessge()	{		return "Detail Message: "+x+"super.getmessage()";	}}

异常与日志 简单说明

package org.rui.ExceptionTest;import java.io.PrintWriter;import java.io.StringWriter;import java.util.logging.Logger;  public class LoggingExceptions{	 public static void main(String[] args) {							try {					throw new LoggingException();				} catch (LoggingException e) {					System.err.print("Caught: "+e);				}								try {					throw new LoggingException();				} catch (LoggingException e) {					System.err.print("Caught2: "+e);				}						} }  class LoggingException extends Exception{	private static Logger logger=Logger.getLogger("LoggingException");		public LoggingException() {		StringWriter trace=new StringWriter();		printStackTrace(new PrintWriter(trace));		logger.severe("severett:"+trace.toString());	}}

package org.rui.ExceptionTest;import java.io.FileNotFoundException;import java.io.PrintWriter;import java.io.StringWriter;import java.util.logging.Logger;  public class LoggingException2{	 private static Logger logger=Logger.getLogger("LoggingException");	 	 static void LogException(Exception e) {			StringWriter trace=new StringWriter();			e.printStackTrace(new PrintWriter(trace));			logger.severe("severett:"+trace.toString());				}	 	 public static void main(String[] args) {				 try {			 throw new NullPointerException();		} catch (NullPointerException e) {			LogException(e);		}								} }