Java反射之Call stack introspection详解

OpenDeclarationStackTraceElement[]java.lang.Throwable.getStackTrace()
ProvidesprogrammaticaccesstothestacktraceinformationprintedbyprintStackTrace().Returnsanarrayofstacktraceelements,eachrepresentingonestackframe.Thezerothelementofthearray(assumingthearray'slengthisnon-zero)representsthetopofthestack,whichisthelastmethodinvocationinthesequence.Typically,thisisthepointatwhichthisthrowablewascreatedandthrown.Thelastelementofthearray(assumingthearray'slengthisnon-zero)representsthebottomofthestack,whichisthefirstmethodinvocationinthesequence.
Somevirtualmachinesmay,undersomecircumstances,omitoneormorestackframesfromthestacktrace.Intheextremecase,avirtualmachinethathasnostacktraceinformationconcerningthisthrowableispermittedtoreturnazero-lengtharrayfromthismethod.Generallyspeaking,thearrayreturnedbythismethodwillcontainoneelementforeveryframethatwouldbeprintedbyprintStackTrace.Writestothereturnedarraydonotaffectfuturecallstothismethod.
Returns:
anarrayofstacktraceelementsrepresentingthestacktracepertainingtothisthrowable.
Since:
1.4

package com.doctor.reflect;
import java.io.PrintWriter;
import java.io.StringWriter;
/**
 * Call stack introspection
 * 
 * @author sdcuike
 *
 *     Created At 2016年8月29日 下午9:40:35
 */
public class CallStackIntrospectionDemo {
	private static final MyLogger logger = new LoggerImpl();
	public static void main(String[] args) {
		logger.logRecord("hello");
		IllegalArgumentException exception = new IllegalArgumentException("IllegalArgumentException");
		logger.logProblem("throwable", exception);
	}
	public interface MyLogger {
		// Types for log records
		int ERROR  = 0;
		int WARNING = 100;
		int STATUS = 200;
		int DEBUG  = 300;
		int TRACE  = 400;
		void logRecord(String message);
		void logProblem(String message, Throwable throwable);
	}
	public static class LoggerImpl implements MyLogger {
		@Override
		    public void logRecord(String message) {
			Throwable throwable = new Throwable();
			log(message, throwable.getStackTrace()[1]);
		}
		@Override
		    public void logProblem(String message, Throwable throwable) {
			StringWriter out = new StringWriter();
			PrintWriter writer = new PrintWriter(out);
			throwable.printStackTrace(writer);
			writer.flush();
			log(message + out.toString(), throwable.getStackTrace()[0]);
		}
		private void log(String message, StackTraceElement stackTraceElement) {
			String className = stackTraceElement.getClassName();
			String methodName = stackTraceElement.getMethodName();
			int lineNumber = stackTraceElement.getLineNumber();
			System.out.println(String.join(" ", "模拟打印日志:", methodName, className, "" + lineNumber, message));
		}
	}
}

模拟打印日志: main com.doctor.reflect.CallStackIntrospectionDemo 36 hello
模拟打印日志: main com.doctor.reflect.CallStackIntrospectionDemo 38 throwablejava.lang.IllegalArgumentException: IllegalArgumentException
  at com.doctor.reflect.CallStackIntrospectionDemo.main(CallStackIntrospectionDemo.java:38)