创建用于登录的OutputStreamAppender

原学程将引见创立用于登录的OutputStreamAppender的处置办法，这篇学程是从其余处所瞅到的，而后减了1些海外法式员的疑问与解问，愿望能对于您有所赞助，佳了，上面开端进修吧。

成绩描写

关于我的Logback记载器，我测验考试经由过程编程创立1个写进ByteArrayOutputStream的OutputStreamAppender。以下是我到今朝为止的情形：

// Destination stream
ByteArrayOutputStream stream = new ByteArrayOutputStream();

// Get LoggerContext from SLF四J
LoggerContext context = (LoggerContext)LoggerFactory.getILoggerFactory();

// Encoder
PatternLayoutEncoder encoder = new PatternLayoutEncoder();
encoder.setContext(context);
encoder.setPattern("%d{HH:妹妹:ss} %⑸level %logger{三六} - %msg%n");
encoder.start();

// OutputStreamAppender
OutputStreamAppender<ILoggingEvent> appender= new OutputStreamAppender<>();
appender.setName( "OutputStream Appender" );
appender.setContext(context);
appender.setOutputStream(printStream);
appender.setEncoder(encoder);

appender.start();

Logger log = context.getLogger(this.getClass());
log.addAppender(appender);

log.info( "text from logger");

// Output to stdout logback status
StatusPrinter.print(context);

依据我读到的一切实质，这应当是准确的。记载器中的所有实质皆没有会写进流，而且OutputStreamAppender没法依据StatusPrinter的输入准确初初化：

一五:二六:三0,三三0 |-WARN in ch.qos.logback.core.OutputStreamAppender[OutputStream Appender] - Encoder has not been set. Cannot invoke its init method.
一五:二六:三0,三三五 |-ERROR in ch.qos.logback.core.OutputStreamAppender[OutputStream Appender] - Appender [OutputStream Appender] failed to append. java.lang.NullPointerException
 at java.lang.NullPointerException
 at  at ch.qos.logback.core.encoder.LayoutWrappingEncoder.doEncode(LayoutWrappingEncoder.java:一三五)
 at  at ch.qos.logback.core.OutputStreamAppender.writeOut(OutputStreamAppender.java:一88)
 at  at ch.qos.logback.core.OutputStreamAppender.subAppend(OutputStreamAppender.java:二一二)
 at  at ch.qos.logback.core.OutputStreamAppender.append(OutputStreamAppender.java:一0三)
 at  at ch.qos.logback.core.UnsynchronizedAppenderBase.doAppend(UnsynchronizedAppenderBase.java:88)
 at  at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:四8)
 at  at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:二七二)
 at  at ch.qos.logback.classic.Logger.callAppenders(Logger.java:二五九)
 at  at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:四四一)
 at  at ch.qos.logback.classic.Logger.filterAndLog_0_Or三Plus(Logger.java:三九五)
 at  at ch.qos.logback.classic.Logger.info(Logger.java:五九九)

我被LayoutWrappingEncoder.doEncode(LayoutWrappingEncoder)的正告以及NPE易住了。我正在树立附带器上的编码器。

推举谜底

翻了翻源代码，发明必需在输入流之前树立编码器：

OutputStreamAppender<ILoggingEvent> appender= new OutputStreamAppender<>();
appender.setName( "OutputStream Appender" );
appender.setContext(context);
appender.setEncoder(encoder);  // <-- must be set before outputstream
appender.setOutputStream(printStream);

佳了闭于创立用于登录的OutputStreamAppender的学程便到这里便停止了，愿望趣模板源码网找到的这篇技巧文章能赞助到年夜野，更多技巧学程不妨在站内搜刮。