title: How to disable PDFBox warn logging
body: <p>I have a simple java console application. pdfbox is utilized to extract text from PDF files. But there is continuous info printed in console:</p>
  
  <pre><code>十一月 29, 2017 9:28:27 下午 org.apache.pdfbox.pdmodel.font.PDSimpleFont toUnicode
  警告: No Unicode mapping for 14 (145) in font GGNHDZ+SimSun  
  十一月 29, 2017 9:28:27 下午 org.apache.pdfbox.pdmodel.font.PDSimpleFont toUnicode
  警告: No Unicode mapping for 28 (249) in font LNKLJH+SimSun
  十一月 29, 2017 9:28:27 下午 org.apache.pdfbox.pdmodel.font.PDSimpleFont toUnicode
  </code></pre>
  
  <p>I really want to remove this information from the console. And I use logback for logging, the logback.xml is just like:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration&gt;
  &lt;logger name="org.apache.pdfbox" level="ERROR"/&gt;
  &lt;timestamp key="timestamp-by-second" datePattern="yyyyMMdd'T'HHmmss"/&gt;
  &lt;appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"&gt;
      &lt;!-- encoder 默认配置为PatternLayoutEncoder --&gt;
      &lt;encoder&gt;
          &lt;pattern&gt;%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n&lt;/pattern&gt;
      &lt;/encoder&gt;
  &lt;/appender&gt;
  &lt;appender name="FILE" class="ch.qos.logback.core.FileAppender"&gt;
      &lt;file&gt;logs/test-${timestamp-by-second}.log&lt;/file&gt;
      &lt;append&gt;true&lt;/append&gt;
      &lt;encoder&gt;
          &lt;pattern&gt;%-4relative [%thread] %-5level %logger{35} - %msg%n
          &lt;/pattern&gt;
      &lt;/encoder&gt;
  &lt;/appender&gt;
  &lt;root level="ERROR"&gt;
      &lt;appender-ref ref="FILE" /&gt;
      &lt;appender-ref ref="STDOUT" /&gt;
  &lt;/root&gt;
  </code></pre>
  
  <p></p>
  
  <p>I have find some answer say that should change the Level. I have changed the level to ERROR. But still not work. I am doubting if the info has something with logback.xml. Because when I remove STDOUT, the pdfbox warn info still print in the console.</p>
  
  <p>Anybody know this case? Thank you in advance.</p>