How to verify the Log4j output?

log錯誤是一種錯誤回報的例外處理機制。

	private StringBuffer mSB;
	private StringBufferOutputStream mSBOutputStream;
	private WriterAppender testAppender;
 
	@Before
	public void setUp() throws Exception {
		mSB = new StringBuffer();
		mSBOutputStream =  new StringBufferOutputStream(mSB);
 
		Writer w = new OutputStreamWriter(mSBOutputStream);
		testAppender = new WriterAppender();
		testAppender.setLayout(new PatternLayout(PatternLayout.DEFAULT_CONVERSION_PATTERN));
		testAppender.setName("test");
		testAppender.activateOptions();
		testAppender.setWriter(w);
 
		LogManager.getLogger(TimeWatcherBuilder.class).addAppender(testAppender);
	}

	@After
	public void teardown() throws SchedulerException{
		LogManager.getLogger(TimeWatcherBuilder.class).removeAppender(testAppender);
	}

• How to redirect the outputstream or writer to loggers writers?