How to disable PDFBox warn logging

I have a simple java console application. pdfbox is utilized to extract text from PDF files. But there is continuous info printed in console:

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

I really want to remove this information from the console. And I use logback for logging, the logback.xml is just like:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<logger name="org.apache.pdfbox" level="ERROR"/>
<timestamp key="timestamp-by-second" datePattern="yyyyMMdd'T'HHmmss"/>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <!-- encoder 默认配置为PatternLayoutEncoder -->
    <encoder>
        <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
</appender>
<appender name="FILE" class="ch.qos.logback.core.FileAppender">
    <file>logs/test-${timestamp-by-second}.log</file>
    <append>true</append>
    <encoder>
        <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n
        </pattern>
    </encoder>
</appender>
<root level="ERROR">
    <appender-ref ref="FILE" />
    <appender-ref ref="STDOUT" />
</root>

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.

Anybody know this case? Thank you in advance.

If the logging was being emitted by Logback then the approach you have tried, for example ...

Adding <logger name="org.apache.pdfbox" level="ERROR"/>
Removing the STDOUT appender

... would work.

However, PDFBox doesn't use Logback, instead it uses Apache Commons Logging (http://commons.apache.org/logging/). There are several ways of disabling Commons Logging:

Disable Commons Logging entirely by adding the following to your Main class' static initialiser block, this must be executed before PDFBOX creates a Log instance:
```
static {
    System.setProperty("org.apache.commons.logging.Log",
                 "org.apache.commons.logging.impl.NoOpLog");
}
```
Disable Commons Logging by passing the following JVM parameter when you start your application:
```
-Dorg.apache.commons.logging.Log=org.apache.commons.logging.impl.NoOpLog` 
```
Disable Commons Logging for the PDFBOX namespace by adding the following to your Main class' static initialiser block, this *must** be executed before PDFBOX creates a Log instance (note: you could alternatively use Level.SEVERE, depending on how much tolerance you have for PDFBOX's log output):
```
java.util.logging.Logger.getLogger("org.apache.pdfbox")
    .setLevel(java.util.logging.Level.OFF);
```